Slevin or Slavin are the Anglicized forms of one of the most ancient and honourable of all surnames. They derive from "O'Sleibhin", descendant of the son (ain) of Sleibh, the latter being Gaelic for a mountain, and denoting a warrior of magnificent stature. Curiously, the name is mostly associated with poetry, the original nameholder being one of the earliest recorded bards (see below), but as he was also a close associate of Malachy, High King of Ireland, in his battles with Brian Boru, killed in 1014, it is probable that he was equally effective in the fighting role. It is also said that another O'Sleibhin was Chief Poet of Oriel, circa 1168, but this is not proven. In 1514, the Liberty Court of Tipperary described one Terrelagh O'Slevin as "pure Irish of the Irish Nation", a description which apparently debarred him from land ownership, although in 1603 the Slevin Clan of County Fermanagh are described as "Coarbs" - or hereditary holders of church lands. In the 1659 "census" the Slevins are recorded as major landholders in County Westmeath, whilst in 1739, William Slevin is noted as a witness at the Church of St. Nicholas Within, Dublin, on June 1st of that year. One of the earliest of the 1846 famine emigrants, who left Ireland for America, was one Thomas Slevin, aged 22 yrs., a passenger on the ship "Cornet" of Liverpool, on May 18th of that fateful year. The first recorded spelling of the family name is shown to be that of Giolla Comhghaill O'Sleighin, which was dated circa 1002 - 1022, the Chief Bard of Ulster, during the reign of Brian Boru, High King of Ireland, 1002 - 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.