Fiach McHugh O ' Byrne Fiach Mac Aodha Ó Broin ( anglicised as Feagh or Fiach McHugh O ' Byrne ) ( 1534 – 1597 ) was Lord of Ranelagh and sometime leader of the Clann Uí Bhroin , or the O ' Byrne clan , during the Elizabethan conquest of Ireland . Background . During the reign of Queen Elizabeth of England , the O ' Byrne clan held sway in the territory of 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 . The territory included the oak wood of Shillelagh , and part of Co . Wexford . The clan was at times reckoned capable of fielding one hundred expert swordsmen and posed an ongoing threat to Tudor authority within the Pale through its raids on the lowlands . It also weighed in the balance of power between various factions and dynasties throughout the southern part of the province of 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 peril of his life to lead the crown troops into the heart of O ' Byrne territory . Sixteen villages were burned and hundreds were slaughtered . Fiach escaped with the loss of two sisters and two foster brothers and in retaliation led 400 followers 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 , including O ' Byrne ' s sister , who was spared by the crown forces . After the death of O ' More , 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 Baltinglas – 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 . In the same month in 1580 , a new Lord Deputy of Ireland , Arthur Grey , 14th Baron Grey de Wilton arrived with 6 , 000 newly recruited troops . He found the country in a nervous state , owing to the threat of Spanish intervention in favour of the rebels . Crown commanders throughout the country were on guard , and Grey was beset at every point of the compass . It was clear that cutting off the source of so many raids against the underbelly of Dublin , within twenty five miles of the city , was necessary . In addition , an offensive into the province of Munster was expected , and before he might engage on that campaign Grey had to deal with the O ' Byrnes to prevent them attacking him in the rear as he marched south . The campaign resulted in the Battle of Glenmalure . Battle of Glenmalure . In 1580 , Grey led his army westward through the Pale , ignoring certain veterans who implored him to delay the campaign . He planned to enter Glenmalure from the neighbouring Glen of Imaal and attack O ' Byrne ' s stronghold ; the enemy was expected to be flushed from its fastness , whereupon the English cavalry would ride them down in their flight . O ' Byrne had remained in the Liffey valley with Baltinglas , but at the approach of the crown army he withdrew into Glenmalure . Grey altered his course and travelled several miles south , where he was joined by Kildare , before heading east in a loop and making an arduous ascent into the mountains . After a row amongst his chief officers , Grey sent out an expedition of half his force in royal livery with their colours aloft . The rebel lookout on the peak of Lugnaquilla sounded the alarm , and Grey ordered his men to descend into the glen with a drum roll . O ' Byrne had concealed his men in the craggy terrain , and the English troops , conspicuous in their red and blue coats and white hose , instantly found themselves sliding along a river course . Decimated by sniping gunfire , they hit bottom fully a mile in depth from the point where the glen was entered . The Irish did not wait : shots were fired from both sides , and the kern descended to engage in hand to hand combat . Grey ' s troops were routed with the loss of hundreds , and much valuable equipment had to be discarded . Grey spurred his cavalry on to check the pursuit and force the rebels back into the glen , but even on the retreat to Dublin the punishment was withering . Despite this disturbing setback , Grey was in a position to post a garrison in the locality , in the hope that this would contain Fiach ; but the raids kept coming , even into the suburbs of Dublin . In the campaign that ensued , O ' Byrne did suffer losses and failed to dislodge the garrison , but he held out , even after the crown had asserted its command in Munster with the massacre at Smerwick of the Papal invasion force . In the following spring , when Grey passed through Wicklow , O ' Byrne showed his forces on the hills and sent sorties to cut off the straggling plate wagons . He insisted that the terms offered to him include a pardon for Desmond and a guarantee of freedom of conscience . But the glens now became so frequented with crown troops , that he was forced to accept the original terms and , once hostages had been given to the government , he received his pardon . Quiet Times . For some years after , O ' Byrne appeared to remain quiet and , following the death of the Earl of Desmond in 1583 , had even received into his territory his old foe , Nicholas White , the first visit to that place by a senior crown judge . He gave his uncle and sons as hostages to the new governor , Sir John Perrot , who hanged a piper sent in by O ' Byrne after a cattle raid which had been carried out to the piper ' s tune . Some of the hostages escaped , but O ' Byrne soon appeared before Perrot in English dress and supplied more hostages . In March 1587 , the Irish wife of the English captain , Sir Thomas Lee , let it be known that her husband was plotting to capture O ' Byrne , and Lee decided to separate from her . In 1589 , 22 O ' Byrne hostages escaped custody – including two of Fiach ' s sons and his brother in law – 11 being recaptured . O ' Byrne ' s docility remained in doubt , and he was soon found attacking Arklow Castle in revenge for a private wrong . Cat and Mouse . In 1592 O ' Byrne involved himself in another escape from Dublin Castle . Hugh Roe O ' Donnell ( later Earl of Tirconnell ) had escaped the castle in the previous year , only to be betrayed while on the run . His second attempt was a success , and although he suffered frostbite O ' Donnell was guided to Glenmalure , whence O ' Byrne despatched him home to the province of Ulster . The grave of Art O ' Neill ( son of Shane O ' Neill ) , a fellow prisoner who died during the escape , lies south - west of Granabeg towards Glenmalure , in the townland of Oakwood . O ' Byrne fell quiet again , but Lee insisted throughout the period 1594 – 96 that he was a traitor to the crown , and a new initiative against him was directed by the lord deputy , Sir William Russell . After the Christmas festivities of 1594 , Russell drove O ' Byrne from Ballinacor in a three - day offensive and garrisoned his house . On their approach to the ramparts of Ballinacor a drum had been accidentally sounded before the troops could reach the gate , which put O ' Byrne on his guard , and the gate was defended while those inside fled to safety . It was a mark of how close the government was coming in its efforts to tame the Wicklow highlands , and a reward of £150 was posted for O ' Byrne ' s capture ( or £100 for his head ) . O ' Byrne and his second wife , Rose O ' Toole , were proclaimed traitors . But days later the Dublin suburb of Crumlin was burned by his son - in - law , Walter Reagh . The flames of the raid were seen in the center of Dublin , and Russell ordered the city gates opened as he sent cavalry in pursuit , but to no avail . In response , a fort was built at Ballinacor with 100 O ' Byrne labourers , and the pressure on the clan territory was increased . Walter Reagh Fitzgerald was captured and hanged alive in chains for 24 hours before being impaled on a spike . Russell set up spring camp at Shillelagh , hunting and fishing and receiving the heads of rebels . But O ' Byrne was elusive , even as he intrigued with Hugh O ' Neill , Earl of Tyrone . The O ' Byrnes executed an attack at Athy , but Fiach denounced the raid . At about this time his wife , Rose O ' Toole , was captured and , upon her conviction for treason by a Dublin jury , sentenced to death by burning ; her life was spared , only because she had been convinced to convey information to Feagh that his son Turlough was betraying him . Consequently O ' Byrne delivered over Turlough , who , refusing to engage in any more schemes to betray his father , was executed . Ulster Alliance . In his negotiations with Russell , during a truce in the Nine Years War , Hugh O ' Neill included terms for the treatment of O ' Byrne , and reinforced his point with the capture of the Blackwater fort , which was said to have been in response to the lord deputy ' s campaign in Wicklow . O ' Byrne sought pardon for himself and his family – excluding his most wayward sons – in the summer of 1596 , by which time he was old and sick . He presented himself on his knees to the council sitting at Dublin , seeking mercy , and was granted his pardon upon petition to the queen . Even so , he was in alliance with O ' Neill , acting as a Leinster base for rebel influence and maintained a threatening force on the borders of the Pale . The fort at Ballinacor was soon recaptured , and the attacks on government forces in Wicklow began again . O ' Byrne had also allied with the O ' Mores , Kavanaghs , O ' Connors and O ' Tooles , and was thought by Russell to be of far greater ability than O ' Neill . However , the rest of the O ' Byrnes were not considered a threat , indeed the clan were divided , with some engaging in the hunting down of Feagh , and a new fort was built at Rathdown . During the winter , Russell scoured the mountains , taking in cattle and heads . He crossed the bridge at Ballinacor ford against resistance on 24 September 1596 and stayed on the mountain with his cavalry . Meanwhile , Captain Lee was sent with a force to Fananerin , on the west side of Glenmalure ( i . e . in Manning ' s bog north of Greenane north of the river ) , where he burned the town before returning to camp . O ' Neill complained of the attacks on O ' Byrne , and Lee was left to engage in sporadic fighting . The government believed that O ' Neill was attempting to divert the attacks , and so Russell made the final push in March 1597 , when he marched over the mountains to Fananerin and on to Ballinacor and into the glen . There he made a show of dining , and knighted an officer in the place where one of the Carews had been slain during Grey ' s campaign in 1580 . Russell withdrew , only to return two months later on the information of the northern branch of the O ' Byrne clan . He was due for recall to London , and it seems that the defeat of O ' Byrne himself had become the ultimate aim of his government . Again the Lord Deputy came to Fananerin ( Sunday , 8 May 1597 ) , with troops converging on the town from three directions . O ' Byrne was in the company of a few swordsmen , who were killed at the first incursion , and fled on foot . He was compelled by exhaustion to seek refuge in a cave , where Captain Thomas Lee caught up with him . He was executed by Lee ' s soldiers , and his own sword was used to cut off his head , which was presented to Russell before his return to Dublin the next day . It was the governor ' s final success in Ireland . Lee later met with O ' Byrne ' s son , Phelim , at Rathmines , and swore the killing had not been of his choice . The Lost Head . O ' Byrne ' s corpse was cut up , and for months the head and quarters hung on pike staffs on the wall over Dublin Castle drawbridge . Several months later , the pickled head was presented to the council secretary at London by an English adventurer , who was disappointed to find that the head - silver due on O ' Byrne had already been paid in Ireland . The queen was angered that " " the head of " such a base Robin Hood " was brought solemnly into England " " . The offending item was given to some lad for burial , but was found a day or two later in Enfield Chase , outside London , perched in the fork of a tree . Descendants . Writing in 2005 , Sean Mac Bradaigh ( p . 57 ) stated " " Many efforts have been made over the years to find modern descendants of the Glenmalur Chief , Feach mac Hugh O ' Byrne . None have met with any notable success . " " Toirdelbhach , Fiach ' s eldest son , was executed on 18 July 1595 . He had two daughters and no sons . Fiach ' s second son , Felim Buidh na Laragh , was an M . P . for County Wicklow and died in 1630 . He married Winifred O ' Toole of Castlekevin ( daughter of Luke ) , who died in 1628 . A son of the couple was Brian O ' Birn of Ballincor , outlawed in 1652 . His son was Colonel Shane mac Brian O ' Birn , who served in the army of the Irish Catholic Confederation in the 1640s . MacBradaigh cites a family genealogy which brings Fiach ' s descendants down to 1875 , in the persons of brothers Alfred and John Byrne of Sleaty , County Laois . Alfred , a soldier , was the eldest and would have been ninth in descent from Felim , his pedigree been Alfred son of Gerald of Sleaty son of Charles of Sleaty son of Gerald of Ballinakill son of Charles son of Edmond of Ballinakill ( died 1737 ) son of Hugh son of Shane son of Brian son of Felim son of Fiach . MacBradaigh agrees that the descent down to Colonel Shane O ' Birn is correct , it been verified in the genealogies of the Gabhal Raghnail . He furthermore is inclined to accept the descent from Edmond O ' Birn of Ballinakill , Clonmore ( died 1737 ) down to Alfred and John . However , he casts grave doubts on the authenticity of Hugh O ' Birn , punative son of Colonel O ' Birn , stating ( p . 58 ) that he " " does not belong naturally in either section . . . . He is called Hugh Gancagh in the description of his punative son Edmond , a description which associates tha latter , and by implication the former , with the place called Clonmore . This makes it apparent that simple ' Hugh O ' Birn ' is meant to be Hugh Gancagh of Clonmore but the later in its full form was the name of an uncle of Feach mac Hugh and brother to his mother Sadhbh . Could a member of Feach ' s family , five generations removed from Sadhbh , by strange chance be named Hugh and be connected with Clonmore ? It seems very unlikely ! Hugh O ' Birn looks phoney , so the genealogy . . . is probably false , but perhaps there is someone out there who could prove me wrong . " " Sadhbh Ni Birn was the daughter of Feidhlim Buidhe O ' Birne of Clonmore , according to p . 110 of the Rathdrum Historical Society , volume 1 , 1998 . Legacy . O ' Byrne role has been overshadowed by accounts of O ' Neill in the Nine Years War . In June 1597 , O ' Neill attacked on several fronts – Carrickfergus , Newry and Westmeath – in retaliation for the killing of his ally . O ' Byrne ' s sons , Phelim and Redmond , survived their father and were active during the remainder of the war . On going north into Ulster , Phelim was given charge of the Blackwater fort . In October 1597 , the brothers returned south and began active operations at O ' Neill ' s direction with a force under the command of the O ' Mores . In 1599 , Phelim had a success against the ill - fated army of the Earl of Essex ( see Essex in Ireland ) , and Redmond returned to O ' Neill ' s ranks . After the war , in 1606 , Phelim and Redmond received grants of what lands were left to them in their father ' s estate . It was under the patronage of Feagh McHugh O ' Byrne that part of the Book of O ' Byrne , a collection of Gaelic poems , was compiled . A manuscript copy was sold at auction in 2000 at Dublin . Feagh McHugh O ' Byrne is celebrated in the song by P . J . McCall ' Follow me up to Carlow ' .