It is in the island of Ireland,hence the Orange Order,and green is associated with catholici
FROM WIK
Ihe Loyal Orange Institution, commonly known as the Orange Order, is an international Protestant fraternal order based in Northern Ireland and primarily associated with Ulster Protestants. It also has lodges in England, Scotland and the Republic of Ireland, as well as in parts of the Commonwealth of Nations and the United States.[1][2][3] The Orange Order was founded by Ulster Protestants in County Armagh in 1795, during a period of Protestant–Catholic sectarian conflict, as a fraternity sworn to maintain the Protestant Ascendancy in Ireland. The all-island Grand Orange Lodge of Ireland was established in 1798. Its name is a tribute to the Dutch-born Protestant king William of Orange, who defeated Catholic king James II in the Williamite–Jacobite War (1689–1691). The Order is best known for its yearly marches, the biggest of which are held on or around 12 July (The Twelfth), a public holiday in Northern Ireland.