She was born Birgit Sandberg in
Gothenburg in 1945. With her first husband, Johnny Strand, she had three daughters. She married fellow historian
Peter Sawyer in 1981. She earned her PhD in History from the
University of Gothenburg in 1981, where she then became associate professor. She held a chair in medieval history at the
University of Trondheim from 1996 to 2007, during which time she moved back and forth between Trondheim and Uppsala. In 2000 she published
The Viking-age Rune-stones: Custom and Commemoration in Early Medieval Scandinavia after encountering runic inscriptions carved by women,
Gerlög and Inga, and becoming intrigued by how women could commission rune stones and use them to stake territorial claims. She was the co-founder of a biennial conference on women in medieval Scandinavia. She was known affectionately as 'Bibi', and she died of lung cancer in 2016. ==Select bibliography==