The name Cogan comes from Milo de Cogan, who was one of the original Norman invaders of Ireland and the right-hand man of the leader Strongbow. As a reward for his service, de Cogan was given large tracts of land in Cork. However, he never gained full control of the lands and was eventually killed by Celts in 1182. As a result, the name had various incarnations in latter years, from Gogan and Goggin to Coogan. Cogan is still prominent in areas of County Cork today. Award-winning Irish author and historian Tim Pat Coogan has written extensively on Irish history, including a biography of Michael Collins and "Wherever Green is Worn: The Story of the Irish Diaspora."