This interesting surname, with variant spellings O'Bannan, (O')Bynnan, (O')Banane, Banan etc., is an Anglicized form of the Old Gaelic O Banain. The Gaelic prefix "O" indicates "male descendant of", plus the personal byname "Banain", a diminutive of "ban" white or fair. Three distinct septs of O'Banain existed in medieval Ireland, the principal branch residing at Leim Ui Bhanain, now Leap Castle, in the barony of Clonlisk i.e. the southern tip of County Offaly. In Petty's "census" of 1659 the name Bannon is numerous in that barony, and also in Lower Ormond, County Tipperary. The surname is also widespread in County Fermanagh where it is recorded from the mid 12th Century. One, Gelasius O'Banan, Abbot of Clones, County Fermanagh, was Bishop of Clogher from 1316-1319. Baile Ui Bhanain, now Ballybannon in the parish of Partry, on the west side of Lough Mask, County Mayo, locates the third sept. On October 23rd 1812 John Bannon and Mary Ann Mayne were married in Clones, and on September 28th 1866, the birth of Michael Bannon was recorded in Roscrea, Co. Tipperary. The first recorded spelling of the family name is shown to be that of Maelpatrick O'Banan, Bishop of Connor, which was dated 1152 "The Pedigree of Muintir Bhanain", Co. Fermanagh, during the reign of Dermot Mac Murrough, King of Leinster, 1134 - 1171. 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.