12th July Parade, Belfast 2024

Ulster Protestants celebrate winning battles on the 12th of July each year. That was the date of the Battle of Aughrim in 1691 when William III's army defeated the Irish Jacobite army loyal to James II. It was one of the bloodiest ever fought in the British Isles, when 7,000 people were killed. At that time, the "Julian" calendar was in use. However, the British switched to the Gregorian calendar in 1752 which changed the battle date to 23rd July. Another, much smaller battle, the "Battle of the Boyne" had been fought on July 1 1690, which became July 11 in the Gregorian calendar. As a compromise, Ulster Protestants decided to celebrate both battles on July 12.