Harold Bluetooth (died about 985), king of Denmark (940?-985), who consolidated the Danish realm as a unitary kingdom. He was the son of Gorm the Old (d. about 940) and inherited his kingdom, centered on Jelling in Jutland. Although he temporarily (974-983) lost southern Jutland to Holy Roman Emperor Otto II, Harold secured all Denmark under his control and extended his rule to much of Norway. Baptized in 960 and thus introducing Christianity into Denmark, he had the famous Jelling rune stone erected in his parents' memory. Harold was fatally wounded during a rebellion by his son and successor, Sweyn I.