Valdemar III of Schleswig

Valdemar III Abelsøn (1238–1257) was the eldest son of King Abel and Matilda and Duke of Schleswig from 1253. When Abel was killed in 1252, Valdemar was a hostage in Cologne and could not claim it, so his uncle Christopher I became king.

Freed by his mother's Holstein kinsmen, he was invested with Schleswig in 1253, and his short rule was spent warring against the king. He died in 1257, leaving it to his brother Eric.