This interesting surname is of Irish origin, and is an anglicization of the Old Gaelic "O'Dobhailein". The Gaelic prefix "O" indicates "grandson" or "male descendant of", plus the personal byname "Dobhailein", from "dobhail" meaning "unlucky" or "unfortunate". Traditionally, Irish family names are taken from the heads of tribes, or from some illustrious warrior, and are usually prefixed by "O" (as above), or "M(a)c", denoting "son of". The principal (O) Devlin sept belonged to County Tyrone; their territory lay on the Tyrone shore of Lough Neagh and was known as Munterdevlin, the first element coming from the Gaelic "muntir", country or territory. Today the name is chiefly found in Tyrone and its adjacent counties. The second main sept belonged to County Sligo, and their territory lay in the barony of Corran. In 1316, one Gillananaev O'Devlin, of the county, standard bearer to the O' Connors, was slain in battle. The name is still prominent in Counties Sligo, Leitrim and Cavan, but has, in some areas, been widely changed to Dolan. Anne Devlin (1778 - 1851) was the faithful servant of the Irish patriot Robert Emmet, who though imprisoned and tortured refused to give information against him. The first recorded spelling of the family name is shown to be that of O' Devlin, which was dated died 1211, Bishop of Kells, during the reign of Cathal "Crabhhearg" (Red Hand), King of Ireland, 1198 - 1224. 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.