In the course of centuries there existed a tension between the Catholics and the Protestants. In Northern Ireland, the population mainly consisted of Catholics.
The Protestants and Unionists refused to listen to them and were insensitive to Catholic grievances. October 1968, the civil rights movement in the USA encouraged the Northern Ireland Civil Rights Association to publicize the gross ill-treatment of Catholics in local housing. Those marches took place in Londonderry ( Derry to the Catholics ) and the route, the people took, provoked the opponents to react. As the police, The Royal Ulster Constabulary, ceased the match by using batons and water cannons, these actions were broadcasted world-wide on television.
Although there had been some reforms introduced in order to calm the campaigners’ demands, other risings of sectarian confrontation in November 1968 and in January 1969 could not have been prevented. The participants were ambushed and attacked by 200 Protestants in the south of Derry.
Those occurences led to the reappearance of the Irish Republican Army in the form of the Provisional Irish Republican Army or also called Provisionals supporting the renewed use of terrorism. That was a reason why the Protestant paramilitary groups or also Loyalists came into being.
Because of violence from both sides, the British government was to send troops to the province in order to maintain order.
Over the next two years, riots and terrorism proceeded in the two main cities, Belfast and Derry.