Kolbeinn Tumason
Kolbeinn Tumason was a member of the Ásbirningar family clan, and was one of the most powerful chieftains in Iceland around the turn of the 13th century. Kolbeinn used his influenced the appointment of his allies into the clergy, such as Bishop Guðmundur Arason. However Guðmundur became a staunch defender of clerical independence, causing their relations to sour. In 1208, Kolbeinn and his followers attacked Guðmundur and his supporters in Hjaltadalur at the Battle of Víðines. Kolbeinn was killed in the battle due to head trauma.