This interesting name of Medieval Irish origin is an alternative form of Riordan, which in Irish Gaelic is O'Riordain. The earlier form, O'Rioghbhardain, reveals its derivation from 'Rioghbhard', meaning Royal bard, with the 'O' denoting 'descendant of'. The sept of O'Riordan belongs exclusively to Munster, originating in County Tipperary, but migrating to County Cork at such an early date, that they can now be regarded as belonging to that county, where they are far more numerous than anywhere else. Throughout history many name bearers had military connections, or were historians. The name was introduced into Barbados, as early as the 17th Century, where it is recorded that one Dinis Reardon was living in St. Peter's Parish, Barbados, (see below). The christening of John Rearden took place on March 19th 1789 at the Lying In Hospital, Endell Street, Holborn, London. The first recorded spelling of the family name is shown to be that of Dinis Reardon, which was dated circa 1678, Census Returns and Parish Registers, Barbados, during the reign of King Charles 11, 'The Merry Monarch', 1660-1685. 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.