Hugh O'Neill, Earl of Tyrone (; – 10 July [<nowiki/>N.S. 20 July] 1616) was an Irish lord and key figure of the Nine Years' War. Known as the "Great Earl", he led the confederacy of Irish lords against the English Crown's conquest of Ireland during the Elizabethan era.

He was born into the O'Neill clan, Tír Eoghain's ruling noble family, during a violent succession conflict which saw his father assassinated. At the age of eight he was relocated to the Pale where he was raised by an English family. Although the Crown hoped to mold him into a puppet ruler sympathetic to the English government, by the 1570s he had built a strong network of both English and Irish contacts which he utilised for his pursuit of political power, eventually becoming one of the richest and most powerful lords in Ireland.

Throughout the early 1590s, Tyrone secretly supported rebellions against the Crown's advances into Ulster whilst publicly maintaining a loyal appearance. He regularly deceived government officials via bribes and convoluted disinformation campaigns. Tyrone introduced a "military revolution" to Ireland with his adoption of both firearms and continental military tactics, making him well-prepared to resist English incursions. In 1591 he caused a stir when he eloped with Mabel Bagenal, younger sister of the Marshal of the Queen's Irish Army. During the Battle of Belleek, Tyrone fought alongside his brother-in-law Henry Bagenal whilst covertly commanding the very troops they were fighting against. After years of playing both sides, he finally went into open rebellion in early 1595 with an assault on the Blackwater Fort. Despite victories at the Battle of the Yellow Ford and Battle of Curlew Pass, the confederacy began to suffer upon the arrival of Lord Deputy Mountjoy and commander Henry Docwra in Ulster. Tyrone was not able to secure reinforcements from Spain until the arrival of the 4th Spanish Armada in late 1601. The confederacy was decisively defeated at the Siege of Kinsale, and Tyrone surrendered to Mountjoy in 1603 with the signing of the Treaty of Mellifont.

Due to increasing hostility against Tyrone and his allies—and possibly believing his arrest for treason was imminent—in 1607 he fled with his countrymen to continental Europe in what is known as the Flight of the Earls. He settled in Rome where he was granted a small pension by Pope Paul V. Despite his plans to return to and retake Ireland, he died during his exile.

In comparison to his aggressive and warlike ally Hugh Roe O'Donnell, Tyrone was cautious and deliberate. A consummate liar, he is considered an enigma to historians due to the elaborate bluffs he employed to mislead his opponents. Although wartime propaganda promoted Tyrone as a "Catholic crusader", historians believe his motivations were primarily political rather than religious—though he apparently underwent a genuine conversion around 1598. He also held the title 3rd Baron Dungannon, and in 1595 he became the last inaugurated Chief of the Name of the O'Neill clan. He was married four times and had many concubines and children.

Family background and early life, 1550–1561

Birth and family

Hugh O'Neill was born in the Gaelic kingdom of Tír Eoghain in Ulster. The O'Neill dynasty were Tír Eoghain's ruling Gaelic Irish noble family, and claimed descent from Niall Ruadh of the Cenél nEógain, who was a descendant of legendary high king Niall of the Nine Hostages. Hugh was the second son of Feardorcha "Matthew" O'Neill, 1st Baron Dungannon (–1558) and his wife Siobhán Maguire (died 1600). Hugh's paternal grandparents were clan chief Conn Bacagh O'Neill, 1st Earl of Tyrone (–1559) and Alison Kelly of Dundalk, a blacksmith's wife. Siobhán was a daughter of Cúconnacht Maguire, Lord of Fermanagh (–1537). Hugh had three brothers: Brian, Cormac MacBaron and Art MacBaron.