For other uses of the term, see Berserker and Berserk . Berserkers (or Berserks) were Norse warriors who wore coats of bear skin (bear-sark) and who were commonly understood to have fought in an uncontrollable rage or trance of fury; the berserkergang. The Úlfhéðnar (singular Úlfhéðinn) mentioned in the Vatnsd?la saga, Haraldskvæði and the Völsunga saga were said to wear the pelt of a wolf upon their heads when they entered battle. (For example: Bernhari, Haimric, Hlodwig, Theudberga, Warinhari etc.) Literary references The earliest surviving reference to the term berserker is in Haraldskvæði, a skaldic poem composed by Thórbiörn Hornklofi in the late ninth century in honour of King Harald Fairhair, the famous ruler of Norway. The poem was preserved by Snorri Sturluson. In