This interesting surname is of Irish origin, and is a patronymic ("mac" denoting the son of), and was originally found in the form "Mag Oireachtach", meaning, son of Oireachtach, a byname meaning, Member of the Assembly. The surname arose in an unusual way; at first it was O'Roduibh, but then taking the name of one namebearer Oireachtach O'Roduibh, in the 12th Century (see below), subsequent member of the clan began using this personal name as their surname. The head of the clan was one of the four Royal Chiefs under O'Conor and prominent in Connacht records, the chief also being the Baron of Athlone from circa 1585. There are at least seventeen different synonyms of Geraghty, including Gerraty, Gearty, Gerty, McGer(r)aghty and Mageraghty. Cornelius Geraghty sailed aboard the "Dromahair", on May 25th 1847 from Sligo to New York. The first recorded spelling of the family name is shown to be that of Oireatach O'Roduibh, which was dated circa 1390, in the "Book of Connacht", during the reign of Art MacMurrough, "King of Leinster", 1376 - 1417. 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.