Birka, Viking Age trading town

On the island of Björkö in Lake Mälaren a trading town grew up in the mid-700s, linking Scandinavia with western Europe and, along the Russian rivers, with the Islamic world. The missionary Ansgar preached there around 830, and the king's estate stood on neighbouring Adelsö. Its graves have yielded silk, Arab silver and weapons, including a much-debated warrior burial of a woman.