O'Neill

Major Gaelic Irish dynasty of Ulster in the later Middle Ages, descended from the Cenél nEóghain branch of the Uí Néill, an ancient family which dominated mid-Ulster in the 9th and 10th centuries.

Having suffered eclipse in the 11th century, the O'Neills recovered status through their leadership of Gaelic resistance to the Anglo-Norman invaders of Ulster, consolidating their pre-eminent position in Ulster at the Battle of Caimeirghe in 1241. However, their defeat at the Battle of Down (1260) ended O'Neill ambitions to restore the high kingship of Ireland. Thereafter, successive O'Neill chieftains sought to stabilize their position through complex armed alliances with other Ulster lords, the Scots, and the great Anglo-Norman houses. Such aspirations reached their peak in 1480 with the conclusion of a marriage alliance with the powerful Fitzgeralds of Kildare.

The fall of the Kildare Fitzgeralds in 1536 left the O'Neill's vulnerable to reprisals from factional rivals. They sought escape by means of a surrender and regrant treaty with the English crown in 1542, under which Conn Bacach O'Neill (1484-1559) surrendered his lands to Henry VIII and received them back, along with the title Earl of Tyrone.

Succession problems arising from the illegitimacy and political weakness of Conn's nominated heir, Matthew (died 1559), led to the rise of another legitimate son, Shane (1530-1567), and violent internecine war. Rejecting Shane's claims to the succession, the crown had him assassinated and restored the original succession through Matthew's younger son Hugh O'Neill, who was created 2nd Earl of Tyrone in 1585. Hugh proved to be highly independent and, after some hesitation, became leader of the Ulster rebellion against government forces in 1594. Following the surrender of the Ulster chiefs in 1603, their sudden departure from Ireland in 1607, known as the Flight of the Earls, was intended to be temporary but ended in prolonged exile in Rome. Although Hugh's nephew, Owen Roe O'Neill, returned to lead an army for the Confederation of Kilkenny in their rebellion of the 1640s, the main O'Neill line died out with Hugh in Rome.