Recorded in various spellings including O'Hagan, Hagan, Hagen, Haggan, Hagon, Hegan and Aiken, this is an Irish surname. Originally from the pre 10 th century Old Gaelic O'hAodhagain, meaning the "male descendant of Aodh", a personal name meaning "fire", Aodh was a pagan god worshipped by the early natives. The great O'Hagan clan originated in the province of Ulster, and the seat of its chief was at Tullahogue, County Tyrone. The chief exercised the hereditary right of inaugurating O'Neill as king or overlord of Ulster. In medieval times, members of the sept were territorial magnates in Counties Monaghan and Armagh, and two places called Ballyagan, (from "baile", a settlement), one in County Derry and the other in Antrim, further locate the O'Hagans. Among the several notable bearers of the name were Thomas O'Hagan, (1812-1885), Lord Chancellor of Ireland, (1868-1874 and 1880-1881), he was created a peer in 1870; and John O'Hagan (1822-1890) was a judge and a patriotic song-writer. Mark O'Hagan was a"Famine immigrant" who sailed to New York on the ship "Rochester" on January 18th 1846. The first recorded spelling of the family name is shown to be that of Ivor O'Hagan, tutor of St. Malachy, which was dated circa 1100, Medieval Records of County Armagh, during the reign of High Kings of Ireland, "with opposition", 1022 - 1166. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.