Question: When did Harald Iii Of Denmark's father die?
Answer: 28 April 1076

Four of his half-brothers were in turn crowned Danish kings, with his youngest brother becoming the Danish king known as Harald IV (Harald the Young), Danish: Harald Olpe. Sweyn II Estridsson  (– 28 April 1076) was King of Denmark from 1047 until his death in 1076. He was the son of Ulf Thorgilsson and Estrid Svendsdatter, and the grandson of King Sweyn I Forkbeard through his mother's line