The Bradley's from Inishowen Co. Donegal
The Irish Bradleys are of true Celtic stock, being part of the Uí Neill tribal grouping, descendants of Niall of the Nine Hostages.
Niall was High King of Ireland from 377 to 404 AD. His father was Eochaidh Muigh-Medon, of the Celtic line of Erimhon or Heremon and his mother was Carthann Cas Dubh, daughter of the king of Britain.
Niall's ancestry can be traced back to Miledh or Milesius of Esbain, King of Spain, whose wife was the daughter of the Egyptian Pharaoh Nectonibus and who was the ancestor of all the Celts in Ireland. From there the line goes back fifteen generations to Niul (from whom the river Nile got its name) who was married to the daughter of Pharaoh Cingris (who drowned in the Red Sea when Moses rejoined the parted waters after the Israelites had made good their escape).
As High King of Ireland, Niall reigned from the ancient Irish royal seat at Tara, in modern Co. Meath. During his reign he conquered all of Ireland and Scotland as well as much of Britain and Wales. He took a royal hostage from each of the nine kingdoms he subjugated, hence his famous nickname.
Niall had twelve sons, eight of whom founded septs: - Eoghan (from whom the Bradleys descend), Laeghaire (or Leary), Conall Crimthann, Conall Gulban, Fiacha, Main, Cairbre and Fergus. The collective descendants of Niall are known as the Uí Néill.
The Bradleys descend from Eoghan (Owen), son of Niall, through Feareadhach, ancestor of Fadhaigh anglicised Fahy, Fahie, and Fay, whose great-great-great-great-great-great-grandson was Brollachan (from the Irish "brollach" meaning "breast") from whom they derived their surname.
Keating's History of Ireland notes, "The O'Brolchains, or O'Brolchans, a name often changed to Bradley, were a numerous clan near Derry, but originally of the Kinel Feradaigh, in the south of Tyrone, and were a branch of the Kinel Owen". The sept was adventurous and no only did they establish a branch in Cork, but a number of them moved to Scotland and from them descend the O'Brologhans of the Western Highlands, whose name has also been anglicised as Brodie in modern times. These, however, must not be confused with the ancient Pictish clan Brodie who took their name from the barony of Brodie in Morayshire, or with the Bradleys of Scotland who took their name from Braidlie in the barony of Hawick in Roxburghshire. A small group of the Derry sept also settled in county Cavan in Ireland where they, strangely, adopted the Norman name Brabazon.
A remarkable number of O'Brallaghans (or rather O'Brollacháin for the English language was then unknown in Ireland) distinguished themselves in the eleventh and twelfth centuries: Maelbrighde O'Brollacháin (died 1029) builder; his sons Aedh (died 1095), professor, and Maelbrighde, bishop of Kildare (1097 - 1100); another, Donal O'Brollachain (died 1202), was Abbot of Derry; while Flaibhertach O'Brollachain (died 1175) rebuilt the Cathedral at Derry in 1164.