Vikings were known to pillage and roam, so it's not all that surprising that they came into contact and traded with peoples from across Europe and parts of Western Asia. What is a little more baffling is the Arabic writing recently identified on 9th- and 10th-century burial costumes discovered in Scandinavia.

Extraordinarily, the textile fragments were found over a century ago and dismissed as fairly standard examples of Viking funeral clothing. It was only recently that Annika Larsson, a researcher in textile archaeology at Uppsala University, spotted the unusual lettering.

The garments come from boat graves unearthed in Birka and Gamla Uppsala in Sweden, but Larsson noticed that the materials weren't local to the area. Tiny geometric designs woven into the fabric distinguished the garments from traditional Scandinavian clothing. It seems they had traveled quite a distance, as the materials were produced in central Asia, Persia, and China.

After further examination, Larsson realized the pattern was ancient Arabic Kufic script. With the help of an Iranian colleague, she translated the two words as "Ali" (the fourth caliph of Islam and cousin to the Muslim prophet Muhammad) and "Allah" (the Arabic word for God). The two words have so far been identified on 10 of almost 100 garment fragments in the collection.

“Perhaps this was an attempt to write prayers so that they could be read from left to right, but with the Arabic characters they should have," said Larsson in the press release. "That we so often maintain that Eastern objects in Viking Age graves could only be the result of plundering and eastward trade doesn’t hold up as an explanatory model because the inscriptions appear in typical Viking Age clothing that have their counterparts in preserved images of Valkyries."