Battle of the Boyne, (July 1 [July 11, New Style], 1690), a victory for the forces of King William III of England over the former king James II, fought on the banks of the River Boyne in Ireland. James, a Roman Catholic, had been forced to abdicate in 1688 and, with the help of the French and the Irish, was attempting to win back his throne.
James, failing to take Londonderry and Enniskillen, had left Ulster as a bridgehead to William and had wasted his best Irish regiments in England and France. In the Oldbridge area, south of the Boyne, he assembled about 7,000 French infantry, some regular Irish cavalry, and untrained Irish infantry and dragoons—altogether about 21,000 men. William led the Dutch Blue Guards, two regiments of French Huguenots, some English, and contingents of Danish, Prussian, Finnish, and Swiss mercenaries—totaling about 35,000 men. Fearing encirclement by William’s cavalry, which crossed the Boyne at Rosnaree on the left and at Oldbridge on the right, James fled hastily from the battle and from the country. The battle was William’s, but the Jacobite army successfully withdrew to carry on the war for another year in Ireland. The Battle of the Boyne is celebrated in Northern Ireland as a victory for the Protestant cause on July 12, which is actually the Old Style date of the more decisive Battle of Aughrim in the following year.
This article uses material from the Encyclopædia Britannica, Inc.