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Here, in order from oldest to most recent are the not-exactly-numerous posts that have appeared on the other site in the past two and a half...

Thursday, 15 December 2022

Professor Grumpy's tips on how to write a lecture quickly (not counting PowerPoint)


Don’t write a script that will take you 50 minutes to read out: this will be far too much information for the students to take in

1: Decide upon the four things you want your students to know about at the end of the lecture. Add Introduction and Conclusion

2. Make those your four main sections and assign ten minutes to each of them. Put those on the left indent of your page. (make a power-point of the section title)

3: Are there key sub-divisions of those areas? If so, divide up your 10 minute- sections accordingly. If not, no worries. Put sub-sections 1 tab indent in from the left hand margin

4: Divide up your 10 minute section (or small sub-section) into the key things that a (say) term 4 student needs to know about. Think of at most one per minute. Write down each basic point 2 tab indents in from the left margin.

5: Will they need illustrations? If so how many (max) will make the point effectively? Remember students will look at illustrations to take them in, so key that into your timing calculations

6: By now the first bits of your lecture should look something like this (use the Word formats for Heading, Heading 1, Heading 2 etc if this will make your notes easier to read and keep track of):


Main Section 1

               Sub-section of main section 1.1






               Sub-section of main section 1.2





Main Section 2

               Sub-section of main section 2.1


I call this a ‘dendritic’ lecture plan because it branches out like a tree

7. For each point jot down what it is that you want to say. If you have a quotation or a reference that you need to read, put that here (or alternatively on a new line indented by three tabs).

8. Write a conclusion (5 mins) that sums up the issues you wanted to put across, and sets up the next lecture – use the same scheme as above if you like.

9. Write an intro (5 mins) that sets the scene for the lecture, why the topic matters/is important for the course, tells the students what you’re going to talk about. PowerPoint with the 4 main sub-headings. Talk them through it.

10. I find that the intro (esp) and conclusion are sometimes the bits that I do want to write out in full, so that I can get the students’ attention, and be clearer and less ‘ummy-and-ahhy’, and have some memorable phrases that they can take away.

11. Once you have that you have 50-minute lecture.

12. Keep your eye on time when you give the lecture, and compare where you are with where you ought to be

13. If, when you give the lecture, you find you have spent too long on a section, you can make up the time by speeding up a bit in the next sections, this is easier done with these bare-bones notes than with a full text.

14. If on the other hand you find you’re going too quickly, recap. Sum up you sections, sub-sections, points even. Introduce your sub-sections and why they matter. No student ever complained about that. True story: once I had so much on that I had no time at all to prepare a lecture I’d never given before (or not in that form anyway) – do not get yourself into this situation – I only had time (like 5-10 minutes beforehand) to write down some key headers. So I spoke slowly and hammered each point home, re-capping, stringing things out. All the while I was thinking ‘my god, this is a disaster’. At the end the students all said, ‘that was such a good lecture tonight [this was when I was at Birkbeck] Guy – it was really clear and helpful.’ As I said, don’t get yourself into that situation (on the other hand, it did kill off the anxiety dreams about unprepared lectures...) but it makes my point about recapping and underlining points never being a bad thing.

15. You can get a lecture text much more quickly this way, one that allows more flexibility and more engagement and which spells out and gets over the main points that you want the students to get.

16. Now you can structure you PowerPoint around your plan. Time saved on text means you have time to make your PowerPoint better. Have a power-point for each sub-section at least, that maps the content (the points) of what you’re going to talk about. A power-point slide per point can help as an aide-memoire and perhaps put up other supplementary information.

17. Power-point: Remember that students stop and read all of the text on a PowerPoint slide even if you tell them not to, so don’t overload slides with text and if you have a long quotation on one, go through it with them.


Archaeology, History and Bad Science: A critique of the analysis of DNA at Szólád (Hungary) and Collegno (Italy). Part 3 (Conclusions)



The aDNA analyses of Szólád and Collegno were combined with study of stable isotopes in the skeletons and then compared with the distribution of grave-goods. The essential overall conclusions were expressed – less than clearly – as follows:

In both Szólád and Collegno this genetic structure mirrors the variation that emerges from their mortuary practices, i.e., how living members of the community represented the individuals that they buried. This perhaps suggests that in these two cemeteries there may indeed have been a biological basis to the notion that long-term shared common descent can shape social identity and that this is reflected in the material culture. However, whether the association between genetic ancestry and material culture reflects specific peoples mentioned in historical texts (i.e., Longobards) or stemmed from a deeper/long-term descent (of mixed barbarian ancestries[[1]]) is as yet unclear.[2]

The stable isotope analysis is very interesting; the discussion of furnished burial deeply flawed. This, however, is not the place to discuss those or to present an alternative interpretation.

Towards the start of the article we read:

We note that we are not aiming to infer Lombard ethnicity, which is a subjective identity.[3]

This is disingenuous. The experiment was designed to examine the Longobard migration, and chose two sites associated with Longobards, excavated and discussed by archaeologists predisposed to read variations in the data on ethnic lines and to see change in material culture as resulting from Longobard migration and who have previously interpreted the sites in those terms. The background to the problem analysed was exclusively expressed in terms of the history of that migration. To say that the implication is not that the supposed incomers are Longobards, defined and unified by their (supposed) ancestry, and that that was what gave rise to the variability in material culture is entirely unconvincing.

But what, if anything, has been shown? It is, to be sure, interesting that the analyses suggest a linkage between different kindreds and particular funerary rites and diets, and that these include the evident incomers at Collegno, but this does not explain the use of those rites. The association between the furnished inhumation burial rite and ‘Germanic’ ethnicity has absolutely no prima facie evidential support whatsoever in the archaeological record. As a rite, it was clearly developed within the frontier provinces of the Roman Empire. As Irene Barbiera has proven, inhumation with weapons was a rite known in Northern Italy before the ‘barbarian migrations’.[4] That cannot be stressed strongly enough. If repeated aDNA studies reveal that furnished inhumation was generally employed by incoming groups from Germania Magna, that will demonstrate that this old assumption was the luckiest guess in the history of archaeology! It will not, however, explain why these groups, with no prior history of using the rite before their migration, suddenly decided to employ it once on Roman or formerly Roman territory, or retrospectively confer methodological or logical rigour on the initial assumption.

The analyses made no linkage between the incoming group in Collegno and the supposedly immigrant group at Szólád, other than the broad similarity of their genetic make-up when plotted on PCA diagrams.[5] Close consideration shows them not to overlap by very much even on the analyses’ own terms. The modern geographical regions associated with the supposedly incoming, ‘northern’ groups are moreover very broad. But let us in any case accept this conclusion. Does it necessarily say anything about the migration of Longobards? Think of all the other possible explanations. If the Collegno incomers do have, loosely, ‘central European DNA’ could they not (as the authors admit) be descended from Ostrogoths, or from any of the barbarians who made up Odoacer’s army? For that matter, although growing up in the locality, why can the different ‘southern’ kindreds at Collegno not belong to either of those groups? Furthermore, what if they were descended from ‘Romans’ who had moved back from the transalpine provinces?[6] Some of the areas from which the alleged newcomers might have come, according to the genetic evidence, lie inside the Empire. All these possibilities are entirely consistent with the experiment’s results.

The authors claim that the results are ‘consistent with an origin of this [putatively immigrant] group east of the Rhine and north of the Danube and we cannot reject the migration, its route, and settlement of the Longobards described in historical texts.’[7] Indeed they are, but they are at least as consistent with a wide range of alternative interpretations and do nothing to render the authors’ preferred reading more plausible than the others.  In short, the Szólád/Collegno analyses involved an experiment set up with a series of interpretive conclusions in mind; that experiment did nothing to rule those out, so it is implied that they have been confirmed. This is bizarre. Traditionally, scientific method proceeds by deduction, by ruling explanations out, rather than simply picking, out of a wide range of possibilities, the one that accords with the analysts’ preconceptions on the grounds that it had not been excluded by the experiment. There is actually very little that is ruled out by this experiment.

Let us suppose, though, that in spite of all my misgivings the analyses had revealed the arrival of Longobards at Collegno and that they were the people using grave-goods. As noted, it would still not explain their decision to use that rite; it would certainly not authorise us to describe the rite and its analogues as Longobard or Barbarian. What would it tell us? That there was a Longobard migration into Italy and, perhaps, that it contributed to stress and social competition at a local level? We knew this. No one to my knowledge is denying – or has ever denied – that there was a Longobard migration, or that it involved the usually-cited numbers of people: perhaps 100,000. In other words, the most positive reading of the results, and one, let me repeat, that by no means automatically emerges from the data, would tell us absolutely nothing that we did not already know and, with considerable likelihood, not even that. Forcing the data into the support of that maximalist reading potentially obscures what they might be saying about a broader and more interesting range of topics.

The Szólád/Collegno experiment – like many other studies of this sort – offers us, by way of conclusions, a choice between the obvious – something we already knew and no which sane person doubted (people moved into the Roman Empire from Barbaricum) – and the impossible – that no one moved and populations were entirely homogeneous. Hence, they frequently rely on setting up the second alternative as a straw man.

[1] Why ‘barbarian’?

[2] Amorim et al. ‘Understanding’, p.8.

[3] Amorim et al. ‘Understanding’, p.2.

[4] I. Barbiera, ‘Remembering the Warriors: Weapon Burials and Tombstones between Antiquity and the Early Middle Ages in Northern Italy’, in Post-Roman Transitions: Christian and Barbarian Identities in the Early Medieval West, ed. W. Pohl & G. Heydemann (Turnhout, 2013), pp.407-35.

[5] Amorim et al., ‘Understanding’, fig 2a, 2b.

[6] As is famously recorded in Eugippius’ Life of Severinus. Life of Severinus: Eugippius. The Life of St. Severin, trans. Bieler, L., (Washington, 1965).

[7] Amorim et al. ‘Understanding’, p.9.

Archaeology, History and Bad Science: A critique of the analysis of DNA at Szólád (Hungary) and Collegno (Italy). Part 2 (Method; Results).


Imagine a historical study that claimed that a general north-south division was visible in, for the sake of argument, the prologues of medieval charters and that this model had predictive value, such that the geographical origin of a charter could be accurately discerned from the sequence, appearance, or non-appearance of particular phrases. This would be quite an assertion, if not necessarily implausible. Imagine, however, that this model had been constructed from a sample of no fewer than 2,233 charters from Switzerland and southern Europe but of only 179 from northern Europe. The claim would – at best – be regarded as shaky. Yet, the geographical distribution of the modern DNA samples against which the aDNA extracted at Szólád and Collegno were compared takes exactly this form. The POPRES (POPulation REference Sample) data base,[1] the largest of those used to establish the distribution of genetic types across modern Europe, contains 1349 subjects from Switzerland, 599 from the United Kingdom, 147 from France, 131 Portuguese subjects, 114 from Italy and 92 from Spain. For the variable ‘Country of Father’, the uneven distribution was skewed further: 1,404 samples from Switzerland, 310 from Italy, 184 from Spain, 177 from France and 158 from Portugal, compared with 91 from Germany, 50 from Belgium and 38 from England.[2] That latter pattern was repeated across the other country of parent or grandparent variables. Every other nation represented, and from which regional characteristics were constructed, contained a few dozen individuals at most. Remember, too, that that the Swiss and southern European subjects were drawn from a population of 193.185 million people: they represented, in other words, just over a thousandth of one percent of the modern population. Even the largest sample, which happened to be taken from the smallest population (that of Switzerland), represents only a hundredth of 1% of the latter. The whole POPRES reference population totals only 5,886 subjects reduced, after quality-control procedures, to 3,082. These are infinitesimally small samples.

The POPRES data was compiled from ten collections with the overall aim of providing useful material ‘for population, disease, and pharmacological genetics research’.[3] Its UK data came overwhelmingly from a sample of 431 South Asian and 938 Northern European subjects, aged between thirty-five and seventy-five, collected from fifty-eight GPs in west London for the purposes of research into cardiovascular illness. The largest population (2,809 subjects) was assembled from the Centre Hospitalier Universitaire Vaudois in Lausanne (hence the dominance of Swiss and southern European samples). Other collections included only healthy subjects. Much of the European genetic data was assembled from the declarations of US, Canadian and Australian subjects of their paternal and maternal ancestry. According to the publication of the POPRES project, ‘[t]he second round of quality control included further PCA [Principal Components Analysis] to identify subjects with ... misreported genetic ancestry’.[4] What this means is unclear but it gives the impression that ‘misreporting’ was established upon the basis of perceived statistical anomaly. Another statement of method is worth quoting in full:

Based on this information, we first attributed a best-guess geographic label to each of the family members based on the following rules: 1) missing data was ignored; 2) if ethnicity conflicted with birthplace or first language data, only ethnicity was considered; 3) if birthplace and first language disagreed, a higher level container label was chosen (e.g. an individual who was born in France but reported his first language to be Norwegian was labeled European); and 4) white individuals born in the US or Canada were attributed according to the first language information alone, if other than English.[5]

Such methods and assumptions may be fair enough, especially for the purposes for which the database was assembled, but they might all be subject to discussion if employed to study historical population movement and ethnicity: not a purpose for which the data were collected. Furthermore, there are serious differences in the reliability of these data between their use at the level of population and their employment at the level of individuals.[6]

The other reference populations were smaller than the POPRES sample.[7] The ‘1000 Genome Project’, from which the genetic ancestry of the Szólád-Collegno individuals was estimated, used populations of only 100-200 subjects.[8] Those that were most significant in the discussion of the results were ‘Central Europeans in Utah’ (CEU: 184 samples); ‘Toscani’ project (TSI, from a small town near Florence: 117 samples); Great Britain (GBR: 107 samples); and ‘Iberians in Spain’ (IBS: 162 samples). Statistically we are looking at fragments of droplets in oceans.

The small modern DNA sample was compared with a still smaller (435 subjects)[9] sample of aDNA collected from archaeologically-recovered skeletons of Bronze Age date ‘or more recent’[10] and the conclusion drawn that, over the past three and a half millennia in Europe, there has been only the barest drift of population, generally to the south.[11] It is significant, however, that the distribution of the Bronze Age sample was almost the diametrical opposite of that of the modern reference population: ninety-three subjects from north of the Alps (mostly from Germany), compared with thirty-three from south of the mountains (including only four from Italy).[12] Some areas heavily represented in the modern sample (Switzerland; France, the UK) featured barely or not at all in the Bronze Age reference set. We have no idea what the population of Bronze Age northern Europe was but one imagines that eighty-eight would be a small fraction of one percent of it. This should raise all sorts of red flags. On this statistical basis, the claims made by Amorim and his fellow authors are, to be generous, bold indeed.

The kindreds were illustrated through a comparison of their genetic ancestry, expressed in terms of the admixture of seven types, of which the most important were labelled ‘CEU+GBR’, ‘TSI’ and ‘IBS’ (see above). It might seem fair to refer to ‘CEU+GBR’ as ‘northern’ and ‘TSI’ and ‘IBS’ as ‘southern’. It should be noted though that the analyses of the aDNA were incapable of clearly separating ‘GBR’ and ‘CEU’. The ‘CEU’ population, as will have been noted, was of modern Americans of European descent. How accurate and precise are its results likely to be in a European context? Even without the problems of sample and method, combining these ancestries covers a very broad region of Europe, inside and outside the Roman frontiers, one unlikely to sustain the very precise but sweeping claims made in the article.

This experiment takes data suggesting immobility, constructed at the level of populations, and compares it against data drawn from individuals and putatively showing migration. If, against the backdrop of a 3,500-year-long history of supposedly general population immobility, aDNA taken from sixty-three burials at two different cemeteries revealed, at both sites, evidence of the arrival of genetically distinct populations, this must have been the equivalent of randomly locating the proverbial needle in a haystack, worthy of a media ‘splash’ in itself. The other implication ought to be that – given the supposed genetic difference of the incomers at Collegno from modern north Italians – whatever its scale, this population movement turned out to be a genetic dead-end, leaving no significant trace in the region’s modern population. If so, the value of this research for the study of the Völkerwanderung should be quite the opposite of that which has been supposed.

Finally, it is worth mentioning that one set of results, which lay outside the expected range, was rejected on hypothetical grounds: ‘this sample showed high levels of contamination (which we hypothesize is the result of plastic wares produced in China that were utilized in DNA extraction) and thus the results are unreliable.’[13] If that were the case, surely that whole body of data should be thrown out of the experiment, not just selected results that did not ‘fit’.


We must assume that the laboratory analyses and subsequent mathematical modelling were flawless but there are strong reasons to discount the experiment’s results on the grounds of its set-up and the problems with its samples. Let us nonetheless treat the results on their own terms. My first point concerns the geographical plotting of different genotypes. The SPA (Spatial Ancestry Analysis) plots geographical coordinates for each allele within a Single Nucleotide Polymorphism (SNP) according to the location of the individual from whom the DNA sample was taken.[14] This data can then be used to predict the location of individuals according to the frequency of particular alleles within the SNPs of their genome. After running a series of SPA analyses, the geographical location of the individuals whose DNA was collected could be represented on a graph, using x and y coordinates, in such a way that the means of samples from different regions stood in a spatial relationship to each other that more or less replicated the geographical relationships between those regions. Thus the mean of samples from, say, the Republic of Ireland, United Kingdom and the Netherlands would be located near each other in the top left quadrant of the graph, above and perhaps to the left of the mean for France, and so on. Now, as Yang et al. illustrate, a very similar result can be produced using Principal Components Analysis.[15] If that is so, it must also be the case that geographical coordinates describe (that is to say represent the variation within) the data to a greater degree than variables within the genotypes. Otherwise, the means of samples taken from particular countries or regions would be pulled into clusters according to those genetic variables rather than their geographical relationships. Alternatively the genetic variables have been represented in such a way as to describe the data less well than the geographical coordinates and so allow the latter to determine the plot to a greater extent. Now, for the medical purposes for which SPA or other genetic models were created, this need not be an issue; indeed it might be desirable. For the discussion of historical genetics, however, one is left wondering exactly how significantly the genotypes differ from one another. [I am no longer sure that I have expressed (or got) this quite right, but there’s something very problematic about this mapping and its implications, and the assumptions made about it.] The plotting of individual samples against these geographically-driven plots seems to produce anomalies.

The presentation of the experiment’s results steers the reader towards a particular interpretation. At both Szólád and Collegno analyses suggested the existence of two genetically distinct groups. The argument is that one such group represents ‘northerners’, implicitly immigrants, and the other ‘locals’ (we can bracket the question of whether these assumptions are valid). On the published diagrams the former is coloured blue; the latter red. There is no good reason to have used exactly the same colour-coding at both sites or, alternatively, to have overlaid the results from both sites on the same figures,[16] especially when we might suppose that they represent significantly different populations. Clearly, the reader is intended to associate the two groups at the two sites and to see them as parts of two larger, generally distinct populations – of incoming Longobards and local provincial Romans, respectively. This hampers any critical reading of the data.

The analyses strongly suggested that there were genetically distinct kindreds present at both Szólád and Collegno. They also showed, however, that the two sites’ populations were quite similar overall.[17] Both included people with genetic ancestry of predominantly ‘CEU+GBR’ (‘northern’) type and others with ancestry that was overwhelmingly of ‘TSI’ (‘southern’) type,[18] although most individuals showed combinations of the two. ‘IBS’ ancestry at both was only found in subjects who showed ‘TSI’ ancestry (although in most cases ‘CEU+GBR’ was also present). Both sites contained some people with entirely ‘northern’ and others with entirely ‘southern’ genetic ancestry. On the basis of the genetic data, however, there would be as much reason to suppose that, at least in in Szólád, the people with ‘southern’ ancestry were the incomers, and those with ‘northern’ ancestry the locals, rather than vice versa. That might superficially seem less likely at Collegno but the lack of significant Italian aDNA comparanda means it is possible there too. The – hardly numerous – prehistoric Italian aDNA subjects clustered in a quite different part of the SPA diagram from the Collegno ‘southerners’.[19] That the kindred with ‘northern’ ancestry were newer to the region of Collegno than the other kindreds was only revealed by the isotopic analyses which were, overall, more interesting than the genetic studies. At Szólád those analyses suggested that kindreds of both ancestry types had moved there quite recently.

Two of the analysts’ presuppositions come into play here, neither of which emerges from the data themselves. The first is that the pattern illustrates a specific episode of demographic movement; the similarity results from one population moving to the area of the other. The second is that, more specifically, this episode was the Longobard migration from Pannonia to Italy. Without these, one could argue that the profiles of the two sites revealed that, genetically, populations in sixth-century northern Italy and in Pannonia were fairly similar and attested to continuous movement back and forth between the two regions as one might expect on historical grounds. This is why a control, or other comparanda, was (or were) essential. How likely is it that a sample of any cemetery in the Po Valley, dating to any period between the ‘Celtic’ settlement of Cisalpine Gaul and now, would like Collegno – contain at least some people with genetic make-up suggestive of comparatively recent origins north of the Alps? I would propose that the answer is ‘very likely’.

While difficult and dangerous, population movement across the Alps has been constant since Ötzi the Iceman.[20] The Celtic migration into northern Italy has been mentioned; later, the different regions were part of the same imperial state for the best part of five centuries; Carolingian Italy was politically connected with the Rhine valley, Germany, and Provence and many armies (and doubtless countless individuals) moved back and forth over the mountains. Those contacts continued in the period of the ‘Holy Roman Empire’, bringing French and German troops into the peninsula, as happened again in the sixteenth-century Italian Wars. The ensuing Hapsburg dominance of northern Italy strengthened the already significant ties between that region, southern Germany, and Hungary up to the late nineteenth century. The idea that genetic similarities between Italian and transalpine populations at any point in history can (let alone must) be explained by then recent, discrete large-scale events lacks empirical basis. In other words, while the similarities between the populations of Szólád and Collegno surely attest to individual movement across the Alps, there is no good reason to suppose that they must testify to any particular, large-scale ‘migration event’, or to change rather than stasis in patterns of population movement. None of that (or indeed any of the arguments proposed here) means there was no Longobard migration or that that movement did not involve a large number of people: both facts are incontestable. What they do mean is that the evidence from these sites is not necessarily evidence of that migration, and that traces of that migration need not be expected to be especially clear in the genomes of late antique northern Italians. In many regards the experiment was fundamentally ill-conceived.

Overall, the analyses suggested a generally mixed population of Szólád. The results of Principal Coordinates Analysis (PCA) of Hungarian aDNA samples, when overlaid (using ‘Procrustes’[21]) with the Szólád-Collegno and modern reference samples revealed a distribution that overlapped with the ‘northern’ and ‘southern’ Szólád kindreds.[22] If the authors’ assumptions about long-term population stability between the Bronze Age and the present day, and about their methodology, were correct[23] this evidence would surely not show very conclusively that either group had moved into the region from a significantly distinct area. Analysis of the strontium content of the teeth at Szólád did not suggest that the ‘northern’ group were necessarily more likely to be outsiders than the ‘southern’ group. They were, however, evidently more heterogeneous in origin than the latter. According to the ‘narrative’ the study was supposed to be ‘testing’, barbarian immigrants were heterogeneous but on what basis would one assume that the population of late Roman Pannonia was not? From historical sources we know that it was a frontier province in which garrisons of diverse origins were stationed; in the late fourth century, Goths passed through the region more than once; the fifth century saw several groups, not least the Huns and Ostrogoths, resident there. The latter, of course, later moved to Italy and established a kingdom there.

The results of the analyses, as presented in the diagrams in Nature, seem less than convincing when examined closely. Subjects with different genetic ancestry are plotted against modern and Bronze Age subjects, as mentioned earlier. However, their grouping raises critical issues as the Principal Components Analysis, for whatever reason, pulled the data in such a way as to reveal, in some cases, a greater range within the groups defined by their ancestry than between them. For example, the Szólád ‘northerner’ and the two Szólád ‘southerners plotted nearest the origin lie closer to each other than they do to the members of their groups plotted farthest from the origin. It is also clear that some Principal Components Analyses have described the data far less clearly than others. Something in the data gives us grounds to wonder about the combination of different analyses of different data sets. Is the PCA calling the ‘Admixture’ analyses into question? This especially muddles the results at Szólád. That issue is further obfuscated by the overlaying of the results from both sites on the same plot and the use of the same colours in their representation, discussed earlier.

The ‘northern’ group at Collegno is in fact clustered more compactly, in a different region of the plot from the Szólád ‘northerners’. Indeed we see that the different genetic kindreds at Collegno are far more significantly separated on that plot, something that might support the conclusions the authors wished to draw. However, we also perceive a third group clearly distinguished from both: those with over 50% ‘TSI’ and ‘IBS’ (Tuscan and Iberian) ancestry who, one would have thought, ought to be plotted much further towards the ‘south’ or ‘south-east’ (or lower left-hand) quadrant on the PCA plot rather than in the region where modern Central European subjects cluster. This must question some of the experiment’s assumptions.[24] Ultimately, though, while there are nine ‘northerners’ (with over 70% ‘GBR+CEU’ ancestry) plotted, there are only four with over 70% Tuscan ancestry and four with Tuscan/Iberian. We may wonder why the authors chose to emphasise only the group with Tuscan ancestry as locals when the ‘TSI + IBS’ group could just as easily be called ‘southerners’, unless it was because this was inconvenient for the narrative that they had decided their results should present.

Finally, given the stress laid upon ancestry in the article’s conclusions, the cautionary note sounded recently by Mathieson and Scally is important:

Another source of confusion is that three distinct concepts – genealogical ancestry, genetic ancestry, and genetic similarity – are frequently conflated. ... but note that only the first two are explicitly forms of ancestry, and that genetic data are surprisingly uninformative about either of them.[25]

[3] Nelson MR, et al., ‘The Population Reference Sample, POPRES: a resource for population, disease, and pharmacological genetics research.’ Am J Hum Genet. 2008 Sep;83(3):347-58. doi: 10.1016/j.ajhg.2008.08.005. Epub 2008 Aug 28. PMID: 18760391; PMCID: PMC2556436.

[4] Nelson et al., ‘The Population Reference Sample’.

[6] Mathieson I, Scally A (2020) ‘What is ancestry?’ PLoS Genet 16(3): e1008624. https://doi.org/10.1371/journal.pgen.1008624

[7] The next largest reference population was that created by G. Hellenthal, G.B.J. Busby, et al., ‘A genetic atlas of human admixture history.’ Science. 2014 Feb 14;343(6172):747-751. doi: 10.1126/science.1243518. PMID: 24531965; PMCID: PMC4209567. This contained 1,490 subjects from ninety-five genotyped population groups worldwide (thus an average of fifteen subjects each).

[8] A. Auton et al., ‘A global reference for human genetic variation.’ Nature 526, 68–74 (2015). https://doi.org/10.1038/nature15393. See https://www.internationalgenome.org/1000-genomes-project-publications/

[9] Mathieson et al.’ ‘Genome-wide patterns of selection in 230 ancient Eurasians.’ Nature 528, 499–503 (2015); Mathieson et al., ‘The genomic history of southeastern Europe.’ Nature 555, 197–203 (2018).


[10] ‘For the latter two studies we only utilize individuals dating from the Bronze Age (within which we included the Beaker Culture) or more recent’. K.R. Veeramah, ‘Supplementary Note 6. Modern and ancient reference dataset construction’. Amorim et al. ‘Understanding’, OSM, pp.28-30, at p.29. The implications of the phrase ‘or more recent’ are unclear.

[11] C.E.G. Amorim & K.R. Veeramah ‘Supplementary Note 7. Principal Component Analysis’ analysis’, Amorim et al., ‘Understanding’, OSM, pp.31-35, at pp.32-33.

[12] Mathieson et al., ‘Genome-wide patterns’, Supplementary Data 1; Mathieson et al., ‘The genomic history’, Supplementary Data. Most data were from eastern and south-eastern Europe and western Asia. There were two more Italian aDNA samples from Neolithic subjects.

[13] C.E.G. Amorim & K.R. Veeramah, ‘Supplementary note 7.’, p.31.

[14] Yang, et al., ‘A model-based approach’.

[15] Yang, et al., ‘A model-based approach’, fig.2.e.

[16] Amorim et al. ‘Understanding’, fig.2.

[17] Amorim et al. ‘Understanding’, fig.3.

[18] On which, see above, pp.000.

[19] Amorim et al. ‘Understanding’, fig.2b.

[20] Ötzi, ironically, was included in their ‘Bronze Age’ sample. Above, n.30.

[21] A transformation of one plot so that it overlays another with the best fit.

[22] Amorim et al. ‘Understanding’, fig.2b.

[23] An assumption questioned by the fact that modern Hungarian DNA samples clustered in quite a different part of the diagram; Amorim et al. ‘Understanding’, fig.2a.

[24] See above.

[25] Mathieson & Scally, ‘What is ancestry?

Archaeology, History and Bad Science: A critique of the analysis of DNA at Szólád (Hungary) and Collegno (Italy). Part 1 (Introduction; setting up the experiment).


[This is a critique I wrote to form my part of an article I co-wrote with Prof Martial Staub (Sheffield) about genetics and archaeology. Later I cut it down, with the idea of publishing the more detailed elements as 'online supplementary materials'. It didn't get published, sadly. I think that there were two main problems: one was a significant jump in the scale and breadth of Martial's part and mine; the other was that detailed critique like this is maybe what needs to happen before an article like that under discussion comes out, rather than afterwards. Nonetheless, I think this detailed critique is worth making, and if anyone does know of a journal or other publication that might be interested in considering this (or a shorter version of it), do please let me know.

I have split the piece into three shorter blogs for ease of reading. This part contains the introduction and discussion of the problems involved in the setting up of the 'experiment'; part 2 discusses methods and results; and Part 3 contains the overall conclusions, and an afterword.]


As a more specific focus for our critique, we consider one particular study which made something of a media splash in 2018.[1] This thought-provoking piece compares evidence from a cemetery at Szólád near Lake Balaton in modern Hungary (Late Antique Pannonia) and another at Collegno in Piemonte, Italy, two areas linked historically by the sixth-century Longobard (or Lombard) Migration to Italy. The analyses revealed discrete groups within both cemeteries, showing different genetic traits, which were related to northern and southern Europe. These groups correlated with different methods of burial and (to a lesser degree) in terms of their diet.

When it appeared, the link to the online publication was retweeted by one Twitter account with the claim that ‘Peter Heather was right. The Völkerwanderung was a thing!’[2] We can leave aside for now the point Heather certainly was right, for the very good reason that no serious scholar has ever denied that the ‘Great Migrations’ happened.[3] What requires more rigorous examination is whether this article supports the interpretation of the Barbarian Migrations that lies behind the term ‘Völkerwanderung’: not simply a large-scale, short-term population movement, but one that introduced novel cultural practices into the regions where the migrants eventually settled. More specifically, we can ask whether it does anything to help us ‘understand’ ‘6th-century barbarian social organization and migration’, as its title proclaims. Here the problem might be a disciplinary divergence in the meaning of the phrase ‘understanding society’ but, if viewed in a purely historical or archaeological sense, my answer will be definitive: no, it doesn’t. It describes two situations where people had (in some way) moved into a specific locality from elsewhere and had (possibly) used different burial practices. That is valuable. If, however, we want to understand those specific local phenomena and, a fortiori, if we wish to draw conclusions from them about the wider events of the ‘Barbarian Migrations’, I will demonstrate that we are no further on than when we were at the start. The only way in which the micro (local) and macro (pan-European) phenomena can be linked is via a number of uncritical assumptions, which the publication in question does nothing to interrogate. Those assumptions are, first, that if migration occurred then that must have been ‘barbarian’ and, second, that social organisation and variation in material culture must be explained by migration. In other words, the fact of ‘barbarian migration’ (which no one is denying) is the necessary and sufficient cause for late antique population and cultural change. It is in the current climate of ‘push-back’ against, and indeed flagrant misrepresentation of the views of,[4] those who deny a unique causal primacy to the Völkerwanderung, the enthusiastic expostulation about how science had proven that the Great Migrations were ‘a thing’ finds its context.

A more critical look at the analysis and its approaches is, however, necessary.[5] The popular reception of such studies and the nature of their media coverage are heavily grounded in suppositions that the methods of laboratory science are superior to the inevitably subjective assumptions and opinions of the historical disciplines and the partial – in both senses of the word – nature of their evidence.[6] Popularly, the epistemological claims of ‘hard science’ trump those of the arts and humanities. The Online Supplementary Materials (hereafter OSM) of the article under discussion set out the procedures employed in the laboratory analyses and mathematical modelling. I can see no reason to comment critically on these. It is no part of this discussion to cast – or even to imply – any doubts upon their quality and rigour. Whatever else one might say, it is an impressive piece of mathematical modelling and complex data analysis. My critique departs instead from consideration of the study’s rigour as a scientific experiment and thus confronts the broader epistemological claims. To anticipate my conclusions, my argument will be that – in that more general sense – the experiment represents bad science.

Setting up the experiment

The authors describe the experiment and its results thus:

[W]e obtained ancient genomic DNA from 63 samples from two cemeteries (from Hungary and Northern Italy) that have been previously associated with the Longobards, a barbarian people that ruled large parts of Italy for over 200 years after invading from Pannonia in 568 CE. Our dense cemetery-based sampling revealed that each cemetery was primarily organized around one large pedigree, suggesting that biological relationships played an important role in these early medieval societies. Moreover, we identified genetic structure in each cemetery involving at least two groups with different ancestry that were very distinct in terms of their funerary customs. Finally, our data are consistent with the proposed long-distance migration from Pannonia to Northern Italy. [Emphasis added]

The experiment was designed to confront the following questions:

Were specific barbarian peoples described in texts culturally and ethnically homogeneous populations, or were they ad-hoc and opportunistic confederations of diverse, loosely connected groups? What role did biological relatedness, being that of close kinship relations or long-term shared ancestry, play in the organization of these barbarian communities and how are such relationships related to patterns of material culture? Did this period involve long-distance migrations as described by late antique authors?

The most troubling aspect of the experiment concerns the way it was shaped by assumptions about its likely results. The OSM include a brief history of the Longobards but not one of late antique northern Italy and its long history of social, cultural, economic, and political relationships with transalpine areas. A reader of the article and its supplementary materials can be forgiven for believing – entirely incorrectly – that the Longobard movement was the only significant migration into Italy to occur in the period. Furthermore, the cemetery-sites investigated are located in the regions linked by historical accounts of the Longobard migration. In other words, the selection of data was made on a priori grounds. Now, genetic scientists might be led to believe that the epistemological status of the ‘Longobard’ label or identifier attached to the sites from which their samples were drawn was much more secure than it is in actuality, or that such a label might imply a genetically discrete population. They can understandably not be familiar with the broader historical and archaeological issues to which we shall return. One may therefore assume a ‘good faith’ procedure on their part in accepting certain parameters in the setting up of the experiment.

Fundamentally, though, one must ask where the control sample is. Assessment of the results’ significance requires comparable analysis of other sites either from the same period but not connected by the Longobard migration, or in the same regions but from a slightly earlier period. The main comparative aDNA evidence used was a pan-European range of samples from the Bronze Age, 1500 years or more before the Longobards’ migration.[7] This is insufficient. One needs comparanda from, say, the middle Roman period. A few early medieval samples were considered but their selection was problematic. A cluster taken from a 4th-7th-century English context was listed as ‘Anglo-Saxon’. Others, from the Caucasus, were labelled as being ‘Alans’. This raises questions in the context of a study of Barbarian Migrations as these names are late antique or early medieval ethnonyms not necessarily linked to genetics or to material culture in any straightforward way. In particular, the term ‘Anglo-Saxon’ implies that these subjects had migrated into the Empire, in this case into the diocese of Britanniae. When linked to the burials of supposed migrants in Hungary and Italy it risks giving the impression of a shared ‘barbarian’ origin.

Only six Italian aDNA samples were consulted in the whole analysis, all from prehistory, and three from the same site. On the basis of this lacuna alone, one is entitled to doubt the results’ validity. The authors state that what they consider to be ‘northern’ DNA is otherwise unknown in Italian samples.[8] This is illogical unless one assumes, a priori, that those graves with such DNA at Collegno were not of Italians. The only Italian aDNA from the relevant period to be considered was that at Collegno, so it is equally true to say that ‘northern’ DNA was found in every early medieval Italian population examined in the study. Without appropriate comparanda it is not possible to know how atypical this profile would be for a late antique cemetery in the Po valley. The only mitigation again concerns the information passed to the genetic scientists. If the assumption, made in good faith, was that Szólád and Collegno were both sites that could reasonably be accepted as having had Longobard populations, then the issue of a control might possibly have been seen as moot. If the Longobard nature of these cemeteries, their populations, and some of their material culture is taken as a given, its correlation with other variables being the subject of analysis, it does not need testing.

But therein lies the problem. On what basis is either Szólád or Collegno ‘Longobard’? The assignment of ethnic identities to forms of archaeological evidence has been hotly debated for over thirty years.[9] The Szólád/Collegno analyses were initially intended to contribute critically to this debate. While many archaeologists now accept that giving ethnic labels to forms of material culture is dubious, these reservations and the newer interpretations which they have engendered have been bitterly resisted; Longobard archaeology is one of the more conservative areas in this respect.[10] This problem even affects the sites’ dating. The earliest period of ‘Longobard’ archaeology begins in 568 precisely, because (so runs the argument) there were no Longobards in Italy before 568 and the material is Longobard. The ethnicity of the associated people is thus entirely prejudged. The same is true in Hungarian archaeology where, conversely, Longobard material cannot be later than 568. There is no archaeological reason to suppose that the first phase of ‘Longobard’ burials at Collegno could not belong to a period perhaps ten (or more) years before 568. Archaeological periodisation cannot be fine-tuned to that level of accuracy and the development of its techniques over the past forty years has shown that phases of change can drift back or forward by decades. For example, a key archaeological transition in artefact-forms which, in the 1980s, was dated to ‘c.600’ is now placed closer to 575/80.[11] The extent to which early Italian ‘Longobard’ material is still generally congruent with comparative material from the period after 568 is unclear. Without the influence of the historical record, some of it could unproblematically be placed earlier. Equally, there is no archaeological reason why Szólád could not have been used for a decade or more after 568. Overall, there are no prima facie archaeological grounds for supposing that the earliest phase at Collegno is not contemporary with the last period at Szólád, whether before, after, or straddling 568. This must influence how we employ cemetery evidence to think about trans-Alpine connections and the Longobard migration.

The link between this material and the Longobards’ arrival is, however, too well entrenched in most Italian archaeology to permit detailed or rigorous scrutiny of the idea. Indeed, the archaeology of this period is currently experiencing a backlash against attempts to reassess the role of Barbarian migration in material cultural change, further making critical revaluation unlikely. The lead-author of the OSM Collegno discussion has written a forceful – if unconvincing – defence of the traditional idea that ethnicity is manifest in late antique burial customs[12] and the lead-author of the Szólád discussion subscribes to a similar viewpoint.[13] The team involved in the Szólád-Collegno analyses included only archaeologists who subscribe to traditional ‘ethnic’ readings of material culture so no serious consideration was given to alternative interpretations.[14] Against that background it is extremely difficult to avoid the implication that incomers distinguished from locals are to be identified as Longobards.

We must also scrutinise the assumptions about the nature of population movement, which can be illustrated with three quotations:

While previous sampling from the era has been limited, we note that published fourth- to seventh-century genomes from Britain, Bavaria, Lithuania, and the Caucasus, analysed alongside our own ancient samples, cluster close to their modern counterparts.

We found no evidence that such ancestry was present in northern Italy during this time (who instead resemble modern southern and Iberian Europeans), which would be consistent with inferred long term barriers to gene flow in Europe across the Alps.

Modern European genetic variation is generally highly structured by geography.[15]

The fundamental assumption is of long-term population immobility, against which seemingly rare migration can be set and, one assumes, be clearly identifiable. Whatever the scientific grounds, historically it is a counterfactual. As will be discussed later, movement of individuals or large groups across the Alps, in both directions, has been constant since prehistory. Instead, support was drawn from an article claiming that the study of a person’s DNA allowed their geographical origins to be reliably estimated even to village level.[16] This conclusion was reached from analysis of populations from three islands off Scotland, three villages in the Alps, and three villages in Croatia. When separated by up to thirty miles of sea or several thousand metres of mountain, it is scarcely surprising that marriage tended to take place within each individual locality. The Croatian case study, where such natural barriers were absent, was far less conclusive. Another support was a study of the British Isles which claimed that modern British DNA showed the persistence of the political units of the ‘Dark Ages’[17] but actually came, very clearly, to the hardly staggering conclusion that people in low-lying arable areas find it easier to move around to find sexual partners than those living in the middle of mountain ranges.[18] Some of these issues resurface when considering the experiment’s methods. The logical accompaniment to the idea that difficult physical geography creates barriers to gene-flow – that areas of easier communication might accelerate it – seems not to feature anywhere in the cited literature. The methods of plotting the spatial distribution of particular genetic components[19] assumed a ‘flat earth model’ – in other words, a genetic feature would normally diminish across space in an even fashion. This contradicts the assumption that physical geography presents long term barriers to gene-flow, as indeed does the very wide geographical spread of modern subjects listed as Swiss.


[1] ‘Understanding 6th-century barbarian social organization and migration through paleogenomics’, in Nature Communications (2018) 9:3547 (DOI: 10.1038/s41467-018-06024-4). For interesting discussion of the media and aDNA studies, see, Källén, Anna & Mulcare, Charlotte & Nyblom, Andreas & Strand, Daniel. (2019). ‘Archaeogenetics in Popular Media: Contemporary Implications of Ancient DNA.’ Current Swedish Archaeology. 27. 69-91. 10.37718/CSA.2019.04. I am grateful to Oren Falk for this reference.

[2] This tweet or the account seems subsequently to have been deleted.

[3] Susan Oosthuizen, The Emergence of the English, is the latest attempt to deny that there was an Anglo-Saxon migration but her argument is extremely problematic.

[4] G.P. Brogiolo, ‘Dati archeologici e beni fiscali nell’Italia Goto-Longobarda’ in Between Taxation and Rent: Fiscal Problems from Late Antiquity to the Early Middle Ages/Entre el Impuesto y la Renta. Problemas de la fiscalidad tardoantigua y altomedieval, ed. P.C. Díaz & I. Martín Viso (Bari, 2011), pp.87-105, at p.100; G.P. Brogiolo & A. Chavarría Arnau, ‘Chiese e insediamenti rurali tra V e VIII secolo prospettive della ricerca archeologica’ in ‘Ipsam Nolam barbari vastaverunt’: L’Italia e il Mediterraneo occidentale tra il V secolo e la metà del VI. Atti del Convegno internazionale di studi (Cimitile-Nola-Santa Maria Capua Vetere, 18-19 giugno 2009), ed. C. Ebanista & M. Rotili (Cimitile, Tavolario edizioni, 2010), pp.45-62, at 46-47.

[5] In 2019 I presented a preliminary critique of this piece at the University of Sheffield. The authors’ response, made before the lecture’s text was publicly available (at https://600transformer.blogspot.com/2019/03/the-barbarian-migrations-in-21st-century.html), was dismissive at best. Cp. the similarly aggressive response by the authors of Charlotte Hedenstierna-Jonson et al., “A Female Viking Warrior Confirmed by Genomics,” American Journal of Physical Anthropology 164.4 (2017): 853-60, to Judith Jesch’s similarly blogged response: “Let’s Debate Female Viking Warriors Yet Again,” Norse and Viking Ramblings (9 September 2017) http://norseandviking.blogspot.com/2017/09/lets-debate-female-viking-warriors-yet.html. Källén et al., ‘Archaeogenetics in Popular Media’, p.85. I am grateful to Oren Falk for letting me read his unpublished paper ‘Death and the Shield-Maiden: Viqueering Vikings and Viquens’, a detailed critical discussion of the supposed woman-warrior found at Bjirka and the ensuing debate.

[6] Källén et al., ‘Archaeogenetics in Popular Media’.

[7] Below, n.28.

[8] Amorim et al. ‘Understanding’, p.5.

[9] This debate was reignited by G. Halsall, ‘The origins of the Reihengräberzivilisation: Forty Years on.’, in Fifth-Century Gaul: A Crisis of Identity? Ed. J.F. Drinkwater and H. Elton (Cambridge, 1992), pp.196-207; G. Halsall, ‘Archaeology and the late Roman frontier in northern Gaul: the so-called Föderatengräber reconsidered’, in Grenze und Differenz im früheren Mittelalter, ed. W. Pohl & H. Reimitz (Vienna, 2000), pp.167-80. These studies are reprinted in G. Halsall, Cemeteries and Society in Merovingian Gaul. Selected Studies on History and Archaeology, 1992-2009 (Leiden, 2010), pp.93-130, alongside ‘Commentary 2: Careful with that axe, Eugenius’ (pp.131-67), which responds to critiques made up until about 2010. For similar criticisms of the traditional ethnic reading, see above all, S. Brather, Ethnische Interpretationen in der frühgeschichtliche Archäologie (Ergänzungsbande zum Reallexikon der germanischen Ältertumskunde 42: Berlin, 2004); P. von Rummel, Habitus Barbarus: Kleidung und Repräsentation spätantiker Eliten im 4. und 5. Jahrhundert Ergänzungsbande zum Reallexikon der germanischen Ältertumskunde 55: Berlin, 2007); F.J. Theuws & M. Alkemade, ‘A kind of mirror for men: sword depositions in late antique northern Gaul’, in Rituals of Power. From Late Antiquity to the Early Middle Ages, ed. F.J. Theuws & J.L. Nelson (Leiden, 2000), pp.401-76; F. Theuws, ‘Grave-goods, ethnicity and the rhetoric of burial sites in late antique northern Gaul’, in Ethnic Constructs in Antiquity. The Role of Power and Tradition, ed. T. Derks & N. Roymans (Amsterdam, 2009), pp.283-319.

[10] See the works by Brogiolo, above n,00; V. Bierbrauer, ‘’Zur ethnischen Interpretation in der frühgeschichtlichen Archäologie’, in Die Suche nach den Ursprüngen von der Bedeutung des frühen Mittelalters (Vienna, 2004); Kazanski, M., & P. Périn, 2008. ‘Identité ethnique en Gaule à l’époque des Grandes Migrations et des Royaumes barbares: étude de cas archéologiques’.  Antiquités Nationales 39, pp.181-216. the articles by Giostra and Vida cited below, n. 00

[11] R. Legoux, P. Périn & F. Vallet, Chronologie Normalisée du Mobilier Funéraire Mérovingien entre Manche et Lorraine (3rd revised edition; Condé-sur-Noireau, 2009).

[12] C. Giostra ‘Goths and Lombards in Italy: the potential of archaeology with respect to ethnocultural identification’, Post-Classical Archaeologies 2011, pp.7-36. There is no space for detailed refutation of the argument here.

[13] T. Vida, ‘Conflict And Coexistence: The Local Population Of The Carpathian Basin Under Avar Rule (Sixth To Seventh Century)’, in The Other Europe in the Middle Ages. Avars, Bulgars, Khazars and Cumans, edited by F. Curta, Brill, Leiden, 2008, pp. 13–46. Vida dismisses Brather’s work: ‘Brather’s position may be popular with advocates of a post-processualist critique of both archaeological sources and the methods of the archaeological inquiry, but it rests on wrong assumptions’ (p.15). He presents no substantive reasons why this might be the case. He and Giostra both deploy ‘post-processualism’ – a very loose archaeological school of thought of which neither seems to have a clear understanding – as a sort of bogeyman, and both rely on the heavily criticised notion of a pan-Germanic culture. For recent discussion of the latter, see M. Friedrich & J. Harland (ed.) Interrogating the “Germanic”: A Category and its Use in Late Antiquity and the Early Middle Ages.

[14] The acknowledgements of Amorim et al., ‘Understanding’, include thanks, for ‘helpful’ conversations, to Dr Philipp von Rummel and Professor Frans Theuws, both of whom have published rigorous critiques of the traditionalist ‘ethnic’ reading of grave-goods (above, n.00). These conversations have clearly been ignored.

[15] Amorim et al. ‘Understanding’, p.5, p.5, p.9, respectively.

[16] O’Dushlaine, C., et al. ‘Genes predict village of origin in rural Europe.’ Eur. J. Hum. Genet. 18, 1269–1270 (2010).

[17] Leslie, S., et al. ‘The fine-scale genetic structure of the British population.’ Nature 519, 309–314 (2015).

[18] Readers should note here the significant difference between the proposition that mountain ranges act as barriers to gene-flow across them and the claim that mountains constrain gene-flow among the population living within the range.

[19] Yang, WY., Novembre, J., Eskin, E., & Halperin, E., A model-based approach for analysis of spatial structure in genetic data. Nat Genet 44, 725–731 (2012). https://doi.org/10.1038/ng.2285