This is an Irish clan name of considerable antiquity. It is apparently recorded in the Annals of the Four Masters, that the clan were very powerful before the Anglo-Norman invasion of 1169, and that the principal branch of the clan was to be found in County Offaly. However in the 20th century the nameholders are to be found in either County Monaghan at Carrickmacross, or sometimes in County Donegal. The name is believed to derive from the Gaelic O'Sibhlen, and to translate as the descendant of the swift one, a reference no doubt to a messenger or similar.The nameholders have always been passionate defenders of Irish freedom, and it is probable that their original move from County Offaly to other parts was not voluntary. Although recorded in the 17th century as O'Shevane or O'Shevlin, the O' was dropped by the 18th century, and has not been revived. The clan members were followers of Hugh O'Donnell in the 1601 uprising, the name being spelt at that time as O'Slyvelane, and it was regularly recorded in "Petty'" census of Ireland in 1659. Thomas Shevlin was a volunteer in Lord Blaney's company of Colonel Dongans regisment of foot in 1670. One of the earliest surviving recordings of the surname is that of Teag O'Shevelan in the Hearth Money Rolls of County Mayo in the year 1665. This was during the reign of King Charles 11 of England, 1660 - 1685.