 Waldemar is known as the last in the line of Ascanian margraves starting with Albert the Bear in 1157; he was only succeeded by his minor cousin Henry II, who died one year later.He was a son of Margrave Conrad of Brandenburg-Stendal and his wife Constance, eldest daughter of the Piast duke Przemysł I of Greater Poland.Waldemar was co-regent from 1302, and succeeded as margrave upon the death of his uncle Otto IV in 1308.