Sweyn II "Estridsson". (1020-1074) was King of Denmark 1047-74. Was the son of Sweyn I "Forkbeard"s daughter Estrid. Fought Harald Hardarada in a long war until 1064 when Harald relinquished his claims to Denmark. After that Sweyn begun to build a strong foundation for royal power through cooperation with the church. He completed the final partition of Denmark in to dioceses.

He joined forces with Edgar Atheling when he attempted to regain the English throne from William the Conqueror. However after capturing York Sweyn accepted a payment from William to desert Edgar, who returned into exile in Scotland.