Nine Years' War: Battle of the Yellow Ford: Irish forces under Hugh O'Neill, Earl of Tyrone, defeat an English expeditionary force under Henry Bagenal.

The Nine Years' War was a conflict in Ireland between a confederacy of Irish lords and the English-led government. The war was primarily a response to the ongoing Tudor conquest of Ireland, and was also part of the Anglo-Spanish War and the European wars of religion.

The Battle of the Yellow Ford was fought in County Armagh on 14 August 1598, during the Nine Years' War in Ireland. An English army of about 4,000, led by Henry Bagenal, was sent from the Pale to relieve the besieged Blackwater Fort. Marching from Armagh to the Blackwater, the column was routed by a Gaelic Irish army under Hugh O'Neill of Tyrone. O'Neill's forces divided the English column and a large earthwork stalled its advance. Bagenal was killed by an Irish musketeer, and scores of his men were killed and wounded when the English gunpowder wagon exploded. About 1,500 of the English army were killed and 300 deserted. After the battle, the Blackwater Fort surrendered to O'Neill. The battle marked an escalation in the war, as the English Crown greatly bolstered its military forces in Ireland, and many Irish lords who had been neutral joined O'Neill's alliance.

Hugh O'Neill, Earl of Tyrone 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 in resistance to the Tudor conquest of Ireland under Queen Elizabeth I.

Sir Henry Bagenal PC was marshal of the Royal Irish Army during the reign of Queen Elizabeth I.