Swedish Brother's Feud

The Swedish Brother's Feud (Swedish: Den andra brödrastriden) was a long-term conflict for the throne of Sweden, where Birger Magnusson was the central figure. Birger, after his father Magnus Ladulås died, became the regent of Sweden in the year of 1290. Birgers brothers, Valdemar and Duke Eric, was jealous of his rule over Sweden and merged in an attempt to depose Birger and gain more land of Sweden, Duke Eric and Valdemar with support from Norway, and Birger partly with support from Denmark. The conflict ended in an agreement in 1310, where Duke Eric gained control over western parts of Sweden.

The Håtuna games
in 1306, after Duke Eric and Valdemar had been at a wedding feast in Bjälbo, they met Birger at the kings manor in Håtuna. After the brothers had met in Håtuna, Eric and Valdemar brought Birger to Nyköping, and took him as a prisoner for several years.

Birger was imprisoned from 1306 to 1308, he got freed after he had made plenty of promises, one of them being that Birger would give away half of his power over Sweden to his brothers in exchange of getting peace and truce with them.

Aftermath
In 1317, Birger Magnusson imprisoned his brothers Eric and Valdemar and let them starve to death. It is unclear when and where the brothers died. This action was done in revenge of what Birgers brothers had done against him in 1306, when Birger got imprisoned.