Fiach mac Aodha Ó Broin (anglicised as Feagh or Fiach MacHugh O'Byrne) (1534 – 8 May, 1597) was Chief of the Name of Clann Uí Bhroin (Clan O'Byrne) and Lord of Ranelagh during the Elizabethan wars against the Irish clans.
Arms
Background
During the reign of Queen Elizabeth I of England, the O'Byrnes controlled territory in the Wicklow mountains south of Dublin, covering about . The fastness of the Ranelagh O'Byrnes lay toward the south, at Ballinacor in Glenmalure, where they maintained a fort near to a ford with a bridge and a castle at Drumkitt (now encompassed within Ballinacor House). The territory included the oak wood of Shillelagh and part of County Wexford.
The Kiltimon, Downs, Cloneroe and Newrath branches of the clan were generally loyal to the Crown, having benefited under English law by primogeniture and the system of 'surrender and regrant'. The Ranelagh O'Byrnes were unsubmissive and were reckoned capable of fielding one hundred expert swordsmen, posing a constant threat to Tudor authority within the Pale through raids on the lowlands, which weighed in the balance of power between the Butler (Ormond) and Fitzgerald (Kildare) dynasties in Leinster.
The O'Byrne territory had been under the nominal authority of a sheriff, but in 1562 the task of bringing order to the border area was given to an English captain. So varied were the local allegiances, and so difficult did the territory prove to police, that little was achieved by the crown government and during the rest of the queen's reign (to 1603) the O'Byrnes proved adept at securing official pardons.
Early career
In 1569 the Ranelagh O'Byrnes, under the leadership of Fiach's father, Hugh, had given help to the rebels during the Desmond Rebellions. Fiach (in Irish, the raven) assisted the escape of the imprisoned Edmund Butler, when the latter fell from a rope while climbing from the battlements of Dublin Castle. Thereafter he proved wily and skilful, and ultimately betrayed an ambition to undermine Tudor authority in Ireland.
In 1572, Fiach was charged with complicity in the murder of Robert Browne of Mulcranan, son-in-law of the seneschal of County Wexford, Sir Nicholas White. The crown commander in Wicklow led a punitive expedition from Newcastle near Bray, seizing a mountain man and forcing him at the peril of his life to lead the crown troops into the heart of O'Byrne territory, where sixteen villages were burned and hundreds slaughtered. Fiach escaped with the loss of two sisters and two foster brothers. In retaliation he led 400 men in raids on villages in Wexford, managing to retire to Glenmalure after evading the seneschal's forces. But in August he surrendered custody of the original murderer in return for a pardon and a fine of 20 marks.
Under the government of Sir Henry Sidney, O'Byrne gave support to his own brother-in-law, Rory Oge O'More, the pretender to the lordship of Leix, who broke out in rebellion in 1577. In a bloody fight with Sir John Harrington, many of O'More's household were killed, although O'Byrne's sister was spared by the crown forces. After O'More's death, O'Byrne took in the rebel's son for training at Ballinacor, which by that time had become a martial academy.
O'Byrne was in correspondence with Gerald FitzGerald, 15th Earl of Desmond and never lost touch with Gerald FitzGerald, 11th Earl of Kildare, for whom he did a great favour by hanging an important witness when Kildare was under government investigation. The O'Byrnes continued with their cattle raids, until Fiach made his submission in early 1579 at Christ Church Cathedral, Dublin, where he gave pledges of allegiance and acknowledged the authority of the crown government. This sequence of raids and pardons continued for some time.
Desmond rebellions
In 1579, after succeeding his father in the leadership of the O'Byrnes, Fiach joined with James Eustace, Viscount Baltinglass – despite a history of mutual enmity between their families – during the Second Desmond Rebellion. In the summer of 1580, the Earl of Desmond fled Munster into Queens County (aided by the O'Mores), where he joined the O'Byrnes near the Wicklow border. In August Fiach joined with the Kavanagh clan to ambush crown forces in Idrone (County Carlow): the Irish fought their way through the territory and, after burning the manor house, executed those Kavanaghs who had succumbed to the rule of the English Carew family.