Valdemar I of Denmark

Valdemar I, called the Great (1131–1182), was the son of the murdered prince Canute Lavard. After Eric III abdicated in 1146 he fought a ten-year civil war against rivals Sweyn III and Canute V. When Sweyn murdered Canute at Roskilde in 1157, Valdemar avenged his kinsman, defeating and killing Sweyn at Grathe Heath and uniting Denmark.

Aided by Bishop Absalon, he rebuilt the kingdom and warred down the Wends. In 1168 he stormed Arkona on Rügen, imposing Christianity and Danish overlordship.