Valdemar I Knudsen, also known as Valdemar the Great, was King of Denmark from 1154 until his death in 1182. The reign of King Valdemar I saw the rise of Denmark, which reached its medieval zenith under his son King Valdemar II.

Sweyn III Grathe was the king of Denmark between 1146 and 1157, in shifting alliances with Canute V and his own cousin Valdemar I. In 1157, the three agreed to a tripartition of Denmark. Sweyn attempted to kill his rivals at the peace banquet, and was subsequently defeated by Valdemar I at the Battle of Grathe Heath and killed.