This name, with variant spellings Dorran, Dorrian and O'D(e)oran, is an Anglicized form of the Old Gaelic O'Deoradhain (modern Irish O' Deorain). The Gaelic prefix "o" indicates "male descendant of", plus the personal byname "Deorain", from "deoradh", an exile, wanderer or stranger. The Dorans were one of the seven septs of Leix (O' Doran, O' Devoy, O' Dowling, McEvoy, O' Kelly, O' Lalor, and O' Moore) and they were known as "the great Brehan family of Leinster". The word "brehan" refers to the Gaelic legal system in force before the Norman Invasion on which the family was expert. The Dorans were also noted antiquarians and they kept possession of three manuscript copies of the "Tripartite Life of St. Patrick" for generations. In 1540, they held territory in Waterford and Doransland in that county locates them. Branches of the sept settled in Ulster in Counties Armagh and Down. The first recorded spelling of the family name is shown to be that of Maurice Doran, the Bishop of Leighlin (Leinster), which was dated 1523, murdered by his archdeacon, Kavanagh, during the reign of King Henry V111 of England, known as "Bluff King Hal", 1509 - 1547. 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.