Northern Ireland has been suffering from annual outbreaks of violence as leaders of the divided region try to establish a long-term solution to the thorny issue of parades. The parades are held each year to commemorate the Battle of the Boyne, in which the Protestant King William III defeated the ousted Catholic King James II in 1690. After a stand-off between 5,000 marchers and the police, Unionist rioters set fire to cars and threw petrol bombs, bricks and other missiles at police, burned flags of the mainly Catholic Irish Republic and played sectarian tunes outside Catholic churches.