Why Was Birka Abandoned?

For two centuries, Birka was where the Viking world came to shop. Founded around A.D. 750 on the island of Björkö in Lake Mälaren, Sweden, it was one of a new kind of market town linking chieftains and petty kingdoms across the Baltic. In A.D. 829 a missionary named Anskar, later an archbishop, arrived hoping to convert the Svear to Christianity. He had little success. Then, around 970, Birka simply emptied out. Why?

No journal of Anskar’s survives. Our best written account is the Life of Anskar, written by his successor Rimbert soon after Anskar’s death in 865, and it was meant to celebrate a saint rather than map a town. So archaeology tells most of Birka’s story.

Birka’s Layout

In the Viking Age, Lake Mälaren was still an arm of the Baltic Sea, which let seagoing ships sail right up to Birka. Its streets curved in a crescent along the shore, and wooden jetties on stone foundations reached out into the water for loading and unloading.

Birka’s interior was cramped and likely unhygienic. The wealthy likely lived in longhouses built on artificial terraces overlooking the lake, distancing themselves from the crowded and unsanitary squalor of the town below. Townsfolk built a hillfort at one end of the town. A wall divided the market from the ever-expanding cemeteries outside.

The king lived on the neighboring island of Adelsö, at the royal estate of Hovgården, while his steward ran Birka’s day-to-day affairs.

Birka Abandoned

Birka seems to have been abandoned sometime between A.D. 960 and 975. While the reasons for Birka’s decline remain uncertain, several theories have been proposed. One theory holds that the town lost its economic importance. The decline of Birka coincides with the rise of the Christian town of Sigtuna.

Or nature may have closed the door. Ever since the Ice Age glaciers melted, Scandinavia’s land has been slowly rising. As it rose, water levels around Birka fell, and the harbor may have grown too shallow for larger ships.

Some scholars suggest that Danes or another group attacked Birka. However, there is no archaeological evidence to support this theory.

Although abandoned, Birka’s archaeological significance has earned it recognition as Sweden’s first town and a UNESCO World Heritage site since 1993. The town continues to bring fame and attract new visitors.