Hugh O'Neill, Earl of Tyrone, Defeats the English Forces of His Brother-in-Law, Sir Henry Bagenal, at the Battle of Clontibret, Co. Monaghan

Aodh Mór Ó Néill (anglicised as Hugh ONeill), (c. 1540 - July 20, 1616), was an Irish chieftain of the late 16th century, who became 2nd Earl of Tyrone (known as the Great Earl). ONeills career was played out against the background of the Tudor re-conquest of Ireland, and he is best known for leading the resistance during the Nine Years War (Ireland), the strongest threat to English authority in Ireland since the Anglo-Norman conquest in 1172.

The Battle of Clontibret (1595) was fought in modern County Monaghan in Ulster in northern Ireland during the Nine Years War, between the crown forces of Queen Elizabeth and the rebel army of Hugh ONeill, 3rd Earl of Tyrone. It ended in victory for Tyrone, and was the first severe set-back suffered by the English during the war.

The Battle of Clontibret was essentially a two day running fight, as Bagenals column was ambushed on its way to and from Monaghan town.