The evidence, she added, supported the theory that the Viking settlements in the Malar Valley of Sweden were, in fact, a western outpost of the Silk Road that stretched through Russia to silk-producing centers east of the Caspian Sea.

It is well known that the Vikings traded with the Arab world, and archaeologists have found plenty of Arab coins in Viking settlements. The trade lasted 150 years, beginning in the first half of the ninth century.

But Dr. Larsson said that the silk and other artifacts found in the Viking graves suggested not just trade or plundering — but a deeper cultural exchange and shared ideas.