Why are Protestant Irishmen called Orangemen?
Orangemen are members of the Loyal Orange Institution, familiarly called the Orange Order, a Protestant Irish society founded and flourishing mainly in Ulster. It was established (1795) to maintain the Protestant ascendancy in Ireland in the face of the rising agitation for Catholic Emancipation. Its name is taken from the family name of King William III of England, who defeated King James II in the battle of the Boyne in 1690.
