This most interesting and unusual surname is the Anglicized form of the Gaelic name "O' Daighre", which is composed of the Gaelic prefix "O", meaning "male descendant of" and the personal name "Daighre", fiery. The name is found widespread in Ulster and North Connacht, particularly Derry, where it was borne by a notable ecclesiastical family. The name is sometimes found as Derry, but this is the Anglicized form of another name, "O' Doireidh". More confusion arises between these two names because both were located in the same area of North West Ulster; O' Daighre of Derry Church, with the family of O' Doireidh of Donaghmore found in the nearby diocese of Raphow. Denis O' Diera was Bishop of Mayo from 1574 to 1576. The Hearth Money Rolls for Armagh and Monaghan (1663-1666) often record the name O' Deery and O' Deary. Father Patrick O' Deery (O' Deary and O' Dyry) was a friar of Derry Abbey who was especially mentioned by St. Oliver Plunket to be an exceptionally good man and a great preacher. Edmond Deery, aged 23 yrs., a farmer, was a famine immigrant who left Dublin aboard the "Victory" for New York on May 21st 1847. The first recorded spelling of the family name is shown to be that of Maeliosa O' Doireidh, bishop of Columbkil, which was dated circa 1300, in the "Ancient Irish Records", during the reign of King Edward 1, known as "The Hammer of the Scots", 1272-1307. 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.