O'Connor Faly raided the Pale many times from the early 1520s to the mid-1540s, assuring his political position via alliances with the Earl of Kildare and Lord Deputy of Ireland.
[1] He was born into the O'Connor Faly family of the Kingdom of Uí Failghe,[3] which, by the start of the sixteenth century, had extended their territory westward as far as the River Shannon.
[2] By 1520, Brian O'Connor Faly had become Lord of Offaly,[2] and was "at the height of his power"[1] - though it is uncertain whether he obtained the throne from his uncle An Calbhach by force or succeeded him naturally.
[2] In the early 1520s, O'Connor Faly, Maolruanaidh O'Carroll and Lord of Laois Connell O'More raided the Pale.
[1][2] The three men informed Thomas Howard, Lord Lieutenant of Ireland, that their attack was on the orders of Gerald FitzGerald, 9th Earl of Kildare.
[2] In 1528, during the Earl's detention in England, vice-deputy Richard Nugent, 7th Baron Delvin, attempted to withhold O'Connor Faly's black rents from Meath.
On May 12, O'Connor Faly retaliated by persuading Nugent to the borders of Offaly - under the false impression of a parley - and taking him prisoner.
Thomas Boleyn, Earl of Ossory, made plans with Brian's brother Cahir to secure Nugent's release - but this was unsuccessful.
O'Connor Faly and O'More feared they could lose their patron,[5] and invaded Co. Kildare in late 1546, attacking the Anglo-Irish settlements.
[5][2] When St Leger called Rory O'More to Dublin, O'Connor Faly devastated Laois in his absence.
[6][7] Following a string of losses,[2] O'Connor Faly and Giolla Pádraig O'More fled across the River Shannon into Connacht.
St Leger paid for O'Connor Faly's daughter Margaret to travel to England and petition for her father's release.
[1] However, later the same year, the Earl thwarted St Leger's plan by acknowledging Brian's son Donnchadh as the rightful lord.