This name, with variant spellings Downie and Duwney, has two distinct possible origins, the first being an Anglicized form of the Old Gaelic "O Dunadhaigh". The Gaelic prefix "O" indicates "male descendant of", plus the personal byname Dunadhach, the keeper of a fort, from "dun", a fort. The leading sept of this name belonged to the ancient territory of Ui Maine, (Mid Galway and South Roscommon), and the other chief sept were lords of Luachair, a district lying on the borders of Counties Cork, Kerry and Limerick. Another ancient County Galway name "O Maoldhomhraigh" meaning "descendant of the servant of the church" was initially Anglicized Muldowney, later abbreviated to Downey. One, Mulcahy Muldowney was Bishop of Kilmacduagh in that county from 1570-1610. Downey, and it's variants, may also be of territorial origin from the old barony of Duny or Downie in the parish of Monikie, Angus, Scotland, so called from the Scottish Gaelic "dun", a hill, plus the locational suffix "ach". Duncan de Dunny who witnessed a settlement regarding the boundaries of Tulloch and Conon in 1254 was the first recorded namebearer from this source. William Shaw Downie, the infant son of William and Margaret Downie, was christened at Carnmoney, Antrim, on October 1st 1826. The first recorded spelling of the family name is shown to be that of O'Dunadhaigh, which was dated Circa 1050, in the "The Annals of the Four Masters", during the reign of High Kings of Ireland "with opposition". 1022 - 1166. 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.