Recorded in several forms including O' Mullan, O' Mullane, O' Mullen, Mullan, Mullane, Mullen, and probably others, this is an Irish surname of great antiquity. It derives from the pre 10th century Gaelic surname O' Madain, meaning a descendant of Maolain, a personal byname from "maol", meaning tonsured, and hence describing a monk or holyman. Traditionally, Irish family names are taken from the heads of tribes, revered elders, or some illustrious warrior, and are usually prefixed by "Mac" denoting "son of", or "O", grandson, male descendant of. Three distinct septs of "O'Maolain" existed in Ireland. The first, and most important, belonged to County Galway, and the eponymous ancestor, Mullan, was descended from an early king of Connacht. The second, O'Mullan or O'Mullen, held territory in the Ulster counties of Tyrone and Derry. The most famous of this sept was Shane Crosagh O'Mullan, the Derry rapparee, who flourished circa 1729. In Ulster, Mullan may also be an abbreviated form of "MacMullen", a Scottish surname borne by many of the 17th Century settlers in that province. A third sept of "O'Maolain" was found in the Munster County of Cork where the name is Mullane or Mullins. The mother of the liberator Daniel O'Connell, was an O'Mullane. The first recorded spelling of the family name is shown to be that of Denis O'Mullane. This was dated 1608, in "Records of Ulster", during the reign of King James 1 of England and V1 of Scotland, 1603 - 1625. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.