The Loyal Orange Institution, more commonly known as the Orange Order, is a Protestant fraternal organisation based primarily in Northern Ireland. It also has a significant presence in the Scottish Lowlands and lodges throughout the Commonwealth and United States. The Orange Order was founded in County Armagh in 1795, during a period of Protestant-Catholic sectarian conflict, as a Masonic-style brotherhood sworn to maintain the Protestant Ascendancy. It is headed by the Grand Orange Lodge of Ireland, which was established in 1798. Its name is a tribute to the Dutch-born Protestant king William of Orange, who defeated the army of Catholic king James II at the Battle of the Boyne (1690). Its members wear orange sashes and are referred to as Orangemen. The Order is best known for its yearly marches, the biggest of which are held on or around 12 July ('The Twelfth').