Recorded as O'Kane, O' Keane, O'Cane, O'Caine, Kane, Keane, Kean, Cane, Caine, and possibly others, this is an Irish surname. It derives from the pre 10th century Old Gaelic O'Cathain, mean the male descendant of Cathain, the later being a personal name from "cath", meaning battle. 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. The principal O'Cathain sept originally spelt O' Cathan, belonged to the ancient Ulster territory of Tir Eoghain, and a powerful and important family of O'Kane resided at Keenaght and Coleraine in County Derry. Prior to the 12th Century they ousted the O'Connors of Dungiven from their territory, and occupied the area around the River Roe until the advent of the Ulster Plantation. The O'Cahans are frequently mentioned in the Annals of the Four Masters from the late 12th Century, and Teag O'Cahan was one of the inaugurators of O'Neill, Prince of Tyrone. It is said that the MacCloskeys of County Derry descend from one Bloskey O'Kane, slayer of Murtagh O'Loughlin, heir to the throne of Ireland in 1196. A second main sept of O'Cathan belonged to Thomond counties of Clare, Limerick and Tipperary, where the name is (O') Keane and (O') Kane. A notable bearer of the name was Echlin O'Kane (1720 - 1790), one of the most famous Irish harpers of the 18th Century who played in several European courts. Throughout the many centuries, surnames in every country have continued to "develop," often leading to astonishing variants of the original spelling.