The Ulster O Cathain were part of the Cenel Eoghain, a loose tribal grouping of the descendants of Eoghan, son of Niall of the Nine Hostages. They originated in the Laggan area of Donegal, and from there moved eastwards in the twelfth century, ousting the O?Connors from north Derry and retaining their lordship of Keenaght and Coleraine until the seventeenth century.
A distinct family, the O Cein from Munster, and particularly Co. Waterford, have anglicised their name as "Kean(e)".
In 1890 Keane and Kane were ranked as 88th and 96th most common names, respectively. By 1996 the overall ranks were 65th and 67th. However, the rankings in the Republic and Northern Ireland reveal the ; Kane was 21st in the North but only 145th in the Republic, while Keane was 37th in the south, but only 181st in Northern Ireland.
.John B. Keane (b.1928) , from Listowel Co. Kerry, is one of Ireland?s most popular playwrights. His best-known works include The Field (1965), Big Maggie (1969), and Moll (1972). He has also published 3 novels.
The famous actor Edmund Kean (1787-1833) and his son Charles (1811-1880) were of the Munster Keans.
Another notable member of this family was Molly Keane (1905-1996), who published 10 novels between 1928 and 1952 under the pen-name M.J. Farrell. She had been largely forgotten by the 1980s, when she re-emerged, writing this time under her own name, and published Good Behaviour (1981), widely regarded as her masterpiece, a wickedly witty satire on the decaying world of the Anglo-Irish in which she had grown up.
Roy Keane (1971 - ) is one of the most talented footballers ever to emerge from Ireland, and played a major role in Manchester United?s league and Cup double in 1994.