Canute or Knud Valdemarsen (1207 – 1260) was an illegitimate son of King Valdemar II of Denmark, who became Duke of Revelia, Blekinge and Lolland.^[1]

Canute was the son of the king by his mistress, Helena Guttormsdotter, widow of Danish nobleman Esbern Snare and daughter of Guttorm, Riksjarl of Sweden.^[1] His father gave him lands in Estonia as a hereditary duchy in 1219. He was made Duke of Reval (Tallinn) in 1219, but was dispossessed as Denmark was thrown out by the Estonians in 1227.^[2] As compensation, he was given Blekinge in 1242,^{[citation needed]} which he held until his death. Canute supported the younger rebel brothers, Abel and Christopher, against King Eric IV of Denmark in 1246, and was imprisoned at Stegeborg Castle.^[3] The king forced him to exchange Blekinge temporarily for Lolland, but Blekinge was soon restored to Canute's possession.^{[citation needed]}

Canute left two sons Erik Knudsen Skarsholm (died 1304) and Lord Svantepolk Knudsen (died 1310), as well as a daughter who is said to have married a Folkung.^[3] Canute's land of Blekinge, with Lister, was given to his great-grandson lord Knut Folkason in the 1330s by King Magnus VII of Norway. Lord Knut's heirs continued to claim the lordship.