Since the end of the 14th century, Sweden had been a part of the Kalmar Union with Denmark and Norway. The Danish dominance in this union occasionally led to uprisings in Sweden. During Gustav's childhood, parts of the Swedish nobility tried to make Sweden independent. Gustav and his father Erik supported the party of Sten Sture the Younger, regent of Sweden from 1512, and its struggle against the Danish King Christian II. Following the battle of Brännkyrka in 1518, where Sten Sture's troops beat the Danish forces, it was decided that Sten Sture and King Christian would meet in Österhaninge for