For years, researchers have wondered about the elongated, oddly shaped skulls of women that were found in early medieval burial sites around southern Germany.

First found in Bavaria, a region in southern Germany, around the late 1960s, these elongated skulls date back to about 500 A.D. Binding the womens' heads when they were infants—when skulls are more pliable—likely created the odd shape, reports Erin Blakemore for National Geographic. This left them with distinct, elongated skulls. It’s unclear if the practice here was for beauty or health reasons, but skull modification was a common practice around the world for centuries to show social status, reported Atlas Obscura in 2015, and may even have been practiced as late as 1900s France.

Still, very little else was known about the skulls found in Bavaria or how the practice of skull modification arrived to this part of Europe.

One theory was that it might have arrived by way of the Huns, a nomadic 4th to 6th century culture that lived in Eastern Europe and Central Asia, or another similar group.

Now, a new study is challenging that theory, suggesting that the pointy skulls actually belonged to Bulgarian and Romanian brides who were married off for political alliances, reports Michael Price for Science. The findings were published in the journal PNAS.

For the study, a team including anthropologist and population geneticist Joachim Burger from Johannes Gutenberg University in Germany analyzed DNA from 36 sets of bones found in six cemeteries in southern Germany during the 5th and 6th centuries. Of the 26 female skulls, 14 showed signs of artificial cranial deformation (ACD), or skull modification.

They also looked at five additional samples, including two other women from Crimea and Serbia, also with ACD.

While the men, believed to be farmers, looked very similar, the women didn’t resemble the men at all. Besides the shape of their heads, their DNA revealed that they probably had brown eyes and brown hair, while the men likely had blond hair and blue eyes.

And when the team compared these ancient genes to modern peoples’, they found that the men and the women whose skulls were not modified closely matched northern and central European populations. However, the female skulls with ACD belonged to southeastern European ancestors like Romanians and Bulgarians. (Second-century Romania is considered to be the earliest location in Europe where the practice was common, but there, it was as common for men as for women, Price writes.) One of the women even showed East Asian ancestry.

“Archaeologically, they are not that different from the rest of the population,” Burger tells Blakemore. “Genetically, they are totally different.”

Burger also concluded something fascinating about the women: The skulls might have belonged to high-status or noble southeastern European women who traveled to Bavaria to marry for political alliances. ACD is believed to have been practiced only amongst the wealthy, Price reports.

Not every expert is convinced, though. Israel Hershkovitz, an anthropologist at Tel Aviv University in Israel who specializes in ancient human anatomy, tells Price: “This is one of the strangest things I’ve ever read… I don’t buy it.”

He says skulls might have become deformed accidentally — after all, babies’ skulls can deform by being placed on hard surfaces. He also argues that it’s unlikely that a dozen women from a single generation would have be married for political reasons at the same time.

As Price reports, Burger’s study does not include more than a few women with ACD from the same village, so each town could have had a distinct political alliance that would call for a marriage.

The "political marriages" part of Burger’s theory can be debated, but the research debunks the theory about the Huns bringing skull modification to Western Europe.