This interesting surname is of Irish origin, and is an Anglicized form of the Gaelic (O), (Mac) Corcrain, from the personal name "Corcoran", itself coming from the Gaelic "corcair", now used to denote purple but formerly meaning ruddy. The sept called MacCorcoran ("mac" denoting son of) was of some importance in the Ely O' Carroll country; they were still people of substance in Counties Offaly and Tipperary at the end of the 16th Century, and the name is fairly numerous in Counties Tipperary and Cork today. The O' Corcorans ('O' denoting descendant of) belonged to Fermanagh and produced a number of ecclesiastics from the 11th Century to the 15th Century whose field of activity was around Lough Erne. The name is rare there now; probably there was a westward migration as it is found in Counties Mayo and Sligo. The surname dates back to the late 14th Century (see below). Church Records list the marriage of Pat Corcoran to Sally Doran on the 24th January 1700 in Borris, Carlow. One Brigadier General Michael Corcoran (1827-1863), recruited an Irish Legion in the United States in 1861. Edmund O'Corcoran, "the hero of Limerick", during the siege of 1691, was the subject of one of O' Carolan's well-known poems. The first recorded spelling of the family name is shown to be that of Bishop O' Corcoran of Clogher, which was dated 1373, in the Early Irish Records, during the reign of King Edward 111, known as "The Father of the Navy", 1327 - 1377. 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.