The Jewish community of Tàrrega in Catalonia was destroyed in 1348. When their genomes were published in 2026, the researchers asked a simple question: which population, living or dead, do these people most resemble?
They tried modern Turkish Jews, Ashkenazi Jews and Moroccan Jews. They tried Bronze Age Israelites. They tried the medieval Christians of Spain. Every recipe failed but one.
How "failed" is measured
The method is called qpAdm. Given a target population and a candidate source, it asks whether the target can be modelled as coming from that source. It returns a p-value. You can read it simply: a very small number means the model is rejected; a number around 0.05 or above means the model fits.
One source at a time
| Single source tried | p-value | Verdict |
|---|---|---|
| Medieval Jews of Erfurt, Germany (13th–15th c.) | 0.098 | fits |
| Nasrid Granada (14th–16th c.) | 0.011 | rejected |
| Modern Ashkenazi Jews | 0.0024 | rejected |
| Modern Turkish Jews | 0.00086 | rejected |
| Bronze Age Israel | 0.00052 | rejected |
| Modern Moroccan Jews | 0.000013 | rejected |
| Medieval non-Jewish Iberians | 2 × 10⁻¹⁶ | firmly rejected |
| Medieval English Jews (11th–13th c.) | 1 × 10⁻⁶⁹ | firmly rejected |
The only single population that fits is another medieval Jewish community, about 1,200 km away in Thuringia.
Two sources together
A two-source model fits too: Bronze Age Israel plus medieval non-Jewish Iberians, at about 69% and 31% (p = 0.158). The Jews of Tàrrega were, in genetic terms, a people of Levantine origin who had absorbed roughly a third of their ancestry from the Iberians around them.
They were a community, not a family
It matters that this isn't one extended family. The twelve people sequenced are not closely related to each other, so they are independent samples of a community rather than a single household. One of them shows long stretches of identical DNA on both copies of his chromosomes, which the authors read as the background endogamy of a small community rather than a marriage between close relatives.
Why this should change how you think
The striking part is who they did not match. The Jews of 1348 Catalonia were closer to the Jews of medieval Erfurt than to their own Christian neighbours — and closer to Erfurt than to any modern Jewish population, including the Sephardic and North African communities that descend from Iberian Jewry.
That makes sense once you say it. Modern Jewish populations are what happened after 1348: expulsion in 1492, migration across the Mediterranean and beyond, and five more centuries of admixture. "Sephardic" in 1348 meant a living community with its own genetic profile, and no modern group is a frozen copy of it.
For anyone testing themselves against "Sephardic" reference populations, that is the lesson. Don't compare yourself only against the descendants when the ancestors are available. A medieval Iberian Jew is a better reference for a converso ancestry question than a modern one — and the six Tàrrega individuals with enough data to use are exactly that.
Sources
- Santos et al., Genes 17(3):358 (2026), Supp. Tables S5 and S15. Data CC-BY.