Harald III, called The Hard Ruler (Norwegian Hårdråde) (1015-1066), king of Norway (1047-1066), a descendant of Harald I. Harald participated in the Battle of Stiklestad in 1030, fighting beside his half brother, King Olaf II, against Norwegian rebels aided by Denmark. Olaf was killed in the battle, and Harald, then in his teens, fled abroad. During the course of his travels over the next 14 years, Harald visited several Russian cities and, in 1033, entered the service of Zoe, empress of the Byzantine Empire, becoming head of the Varangian guards. His exploits in the Mediterranean are described in the Heimskringla, by the Icelandic historian, poet, and political leader Snorri Sturluson. Harald returned to Norway in 1046, and his nephew, Magnus I (the Good), who was then king, gave him half the kingdom in return for half the treasure Harald had amassed in the East. On the death of Magnus a year later, Harald became sole ruler. He warred against the Danes until 1064. In 1066 he joined with Tostig, earl of Northumbria, in warfare against Tostig's brother, Harald II of England. He was killed at the Battle of Stamford Bridge in England on September 25, 1066.