The Kingdom of Uí Fháilghe, Uí Failge or Uíbh Fhailí was a Gaelic-Irish kingdom which existed to 1550, the name of which is preserved in the name of County Offaly, Ireland. County Offaly was constructed from elements of a number of ancient Irish Kingdoms of which Uí Failghe was one amongst such as Mide and Munster. In modern territorial boundaries the kingdom today would correspond with County Offaly east of Tullamore, western parts of Kildare and parts of north east Laois. The name was also retained in the names of two baronies in County Kildare that formed part of the kingdom, Offaly East and Offaly West.
Background
Uí Failghe may have existed as a kingdom from the early historic era. It takes its name from the legendary kingFailge Berraide. It successfully fought off encroachments by the Uí Néill, the Eóganachta, and the Normans however with loss of territories. "The traditions of warfare in the fifth century between Ui Neill and Laigin in Brega and Mide... the Ui Failgi certainly suffered most material damage through the loss of territory in Offaly and Westmeath". From the mid eleventh century its ruling dynasty adopted the surname Ua Conchobhair Failghe or O Connor Faly. Their seat was originally in Rathangan but moved to Daingean with the Norman arrival. On the death of the last de facto king, Brian mac Chathaoir Uí Chonchúir Fhailí, about 1556, Ui Failghe was divided between Queen's County and King's County when it was shired by Mary I of England during one of the Plantations of Ireland. A portion of the original kingdom was made part of County Kildare. Upon Irish independence 'King's County' was renamed County Offaly, in commemoration of Uí Failghe.
Description
The old territory of Offaly is described by O'Donovan in his Ordnance Survey letters. O'Donovan notes the territory of Ui Failghe, or Ophaley, comprising the baronies of: Geshill, Upper and Lower Philipstown, Warrenstown, and Collestown all in King's County; Ophaley in County Kildare; Portnahinch and Tinahinch in Queen's County. O'Donovan cites O'Heerin as giving that Offaly was originally subdivided into seven cantreds: Tuath Geisille ; Hy-Regan ; Clann-Maoilughra ; Clar Colgain ; Tuath-Maighe or Tethmoy ; Magh Aoife, or Fearann Uí Mhurcháin, ; Tuath Leighe. This gives the kingdom an approximately triangular shape, with a southwest corner in the Slieve Bloom Mountains, a southeast corner at Dún Ailinne, and the River Boyne and its tributaries marking its northern border. Keating cites the following family branches as belonging to the Ó Conchubhar Fhailghe: "Ó Caomhánaigh, Ó Tuathalaigh, Ó Branaigh, Mac Giolla Phádraig, Ó Duinn, Ó Díomasaigh, Ó Duibhir, Muintear Riain."
