Harald I Hårfagre
("Fair Hair"), born ~860, died ~940, son of Halvdan Svarte
("the Black") and Ragnhild Sigurdsdatter
The first sole(*) king of Norway. Credited for uniting Norway to a kingdom after the Battle of Hafrsfjord in 872, although the concept of Norway was started before him and not actually finished with the battle. In addition to current territory, he also claimed what is now Swedish Värmland and Hjaltland as well as the Orkneys.
The saga says that Harald decided to unite Norway when he was still very young, and he vowed not to cut his hair or nails until Norway was one kingdom. This is how he got his nickname.
Harald was king until about 932. The saga says he died of old age then, but historians believe him to have lived another 10 years.
See Monarchs of Norway for the royal Norwegian lineage.
(*) Before this, "king" simply meant "noble man" or "chieftain". After the Battle of Hafrsfjord, no one questioned Harald's claim to be king of Norway.