Recorded in many spellings including O'Cullinane, Cullinan, Cullinane, Cullen and occasionally Quillinane, this is an Irish surname. It is derived from the pre 8th century Old Gaelic name O' Cuileannain, with the prefix O' indicating a male descendant of, plus the personal byname Cuilleannain. This is from the elements "cuileann", meaning holy and the diminutive suffix "ain" for son of, to give "The descendant of the son of the holy one". The sept was a branch of the Corca Laoidhe, which comprised the clans of South West Munster, and their territory lay in the barony of Barryroe in County Cork. The surname was well recorded there in Petty's "Census of Ireland" in 1659. Branches of the family spread to Counties Clare and Waterford, and in the latter place, the name took the form Quillinane. Cormac Mac Cuilleannain, the King and Bishop of Cashel was slain in battle in the year 908 a.d. He is said to have compiled the famous "Psalter of Cashel", a genealogical tract. Mullinashee in County Donegal was the seat of another important Cullinan sept, except here the name was changed to Cullen. Amongst the sample recordings in Ireland is the marriage of James Cullinane and Ellen Brosnan on February 12th 1820 at the Roman Catholic Church at Currow in Kerry. The first recorded spelling of the family name is shown to be that of Glaisne O' Cullinan. This was dated 1558 - 1584, in register of the Cistercian abbots of Boyle, in County Roscommon. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.1603.