House of Sverker
After the extinction of the House of Stenkil and the ascension of Sverker I of Sweden in 1130, a civil war commenced. In the beginning, there were several pretenders, of whom Sverker I emerged as victorious, for a time. The antagonists in long run were finally the House of Sverker in Östergötland and the House of Eric in Västergötland and Uppland, which alternated on the throne for several generations, until in the 1220s the Eric dynasty got the upper hand, and the Sverker dynasty became extinct.
As usual in medieval succession rivalries, the final outcome combined the blood of rival lines, as in 1250 Valdemar of the Folkungs ascended the throne, having inherited the Eric dynasty claim from Valdemar's mother and some of the Sverker dynasty claim from Birger's mother.
