The Battle of Grathe Heath was fought in 1157 between the Danish armies of Valdemar I and his rival for the Danish throne, Sweyn III. Valdemar's forces won the battle, and Sweyn III was slain while attempting to flee.

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.