The prestigious Irish family of O'Neil claims descent from Niall Glundubh (Black knee), King of Ireland, who was slain by the Norsemen circa A.D. 919. The legendary Niall of the Nine Hostages (4th Century King of Ireland), was also a remote ancestor. Traditionally, Irish family names are taken from the heads of tribes or some illustrious warrior, and are usually prefixed by "O", male descendant of, or "Mac", denoting "son of". The given name Niall (genitive "Neill") comes from the Gaelic "niadh", champion, and O'Neil has the distinction of being one of the first hereditary surnames ever adopted in Ireland. The O'Neils were the chief family of the Cinel Eoghan, their territory being the Tir Eoghan (modern Co. Tyrone), and their race formed two main branches - the northern Ui Neill of Ulster and the southern Ui Neill of Thomond. The former clan held the title "Earls of Tyrone" and the red hand of Ulster is taken from their Coat of Arms. The latter were chiefs of Bunratty in Co. Clare. In the 14th Century a branch of the Tyrone group known as "Clannaboy", from "Clann Aodha Bhuidhe", settled in Co. Antrim. Their ancestor Aodh Bhuidh (Hugh Boy) O'Neil had been slain in 1283. In the modern idiom the name is spelt O'Neil, O'Neill, Neal(e), Oneile, and Nehill. On May 11th 1873, John O'Neil and Catherine Sullivan were married in Killarney, Co. Kerry. The first recorded spelling of the family name is shown to be that of Domhnal O'Neill, grandson of Niall Glundubh, which was dated circa 1000, in the "Ancient Annals of Ireland", during the reign of Brian Boru, High King of Ireland, 940 - 1014. 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.