Archaeologists Tell the History of the Crusaders Using DNA

Skeletons of Crusaders.
The bones of the Crusaders found in a burial pit in Sidon, Lebanon. (Image: via Claude Doumet-Serhal)

History can tell us a lot about the Crusades, the series of religious wars fought between 1095 and 1291, in which Christian invaders tried to claim the Near East. But the DNA of nine 13th-century Crusaders buried in a pit in Lebanon shows that there’s more to learn about who the Crusaders were and their interactions with the populations they encountered. The work appears in The American Journal of Human Genetics.

The remains suggest that the soldiers making up the Crusader armies were genetically diverse and intermixed with the local population in the Near East, although they didn’t have a lasting effect on the genetics of Lebanese people living today. They also highlight the important role ancient DNA can play in helping us understand historical events that are less well documented.

Senior author Chris Tyler-Smith, a genetics researcher at the Wellcome Sanger Institute, said:

First author Marc Haber, also of the Wellcome Sanger Institute, added:

DNA sequence of nine Crusaders

Archaeological evidence suggested that 25 individuals whose remains were found in a burial pit near a Crusader castle near Sidon, Lebanon, were warriors who died in battle in the 1200s. Based on that, Tyler-Smith, Haber, and their colleagues conducted genetic analyses of the remains and were able to sequence the DNA of nine Crusaders, revealing that three were Europeans, four were Near Easterners, and two individuals had mixed genetic ancestry.

This image shows the bones of the Crusaders found in a burial pit in Sidon, Lebanon.
This image shows the bones of the Crusaders found in a burial pit in Sidon, Lebanon. (Image: via Claude Doumet-Serhal)

Throughout history, other massive human migrations — like the movement of the Mongols through Asia under Genghis Khan and the arrival of colonial Iberians in South America — have fundamentally reshaped the genetic makeup of those regions. However, the authors theorize that the Crusaders’ influence was likely shorter-lived because the Crusaders’ genetic traces are insignificant in people living in Lebanon today. Tyler-Smith said:

This ancient DNA can tell us things about history that modern material can’t. When the researchers sequenced the DNA of people living in Lebanon 2,000 years ago during the Roman period, they found that today’s Lebanese population is more genetically similar to the Roman Lebanese. Haber explained:

These findings indicate that there may be other major events in human history that don’t show up in the DNA of people living today. And if those events aren’t as well-documented as the Crusades, we simply might not know about them. Tyler-Smith added:

That the researchers were able to sequence and interpret the nine Crusaders’ DNA at all was also surprising. DNA degrades faster in warm climates, and the remains studied here were burned and crudely buried. Haber added:

The bones of the Crusaders found in a burial pit in Sidon, Lebanon.
The bones of the Crusaders found in a burial pit in Sidon, Lebanon. (Image: via Claude Doumet-Serhal)

Next, the researchers plan to investigate what was happening genetically in the Near East during the transition from the Bronze Age to the Iron Age.

But they also hope that these kinds of studies will become more commonplace — and more interdisciplinary. Tyler-Smith said:

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