The Troubles?,
The conflict was primarily a political one, but it also had an ethnic or sectarian dimension, although it was not a religious conflict.
The Troubles
The Northern Irish question crystallized on the religious issue. Since the establishment of plantations of British land grabbing in Ulster, and with the defeat of the Catholic Jacobites in 1690 at the Battle of the Boyne, the British Anglican dominated Ulster politically and economically. In 1921, the Anglo-Irish Treaty caused the separation of the six counties of Northern Ireland from the Irish Free State, which became by the adoption of the Constitution in 1937, the Republic of Ireland.
Northern Ireland : religious war or social conflict ?