The "Twelfth" of July is the most important date in the Orange Order calendar and marks the anniversary of the Protestant King William's victory at the Battle of the Boyne in 1690.
Orangemen and women commemorate 'The Twelfth' with band and Orange Order lodge parades across Northern Ireland. Another took place in Rossnowlagh, Co Donegal on Saturday - the last Saturday before the Twelfth.
The site of the Battle of the Boyne, in Co Meath (just outside Drogheda, Co Louth), is a top tourist attraction, and features in a Williamite Trail - an all-Ireland map of locations associated with the Protestant Williamite and Catholic Jacobite armies.
The Orange Order sees itself as a champion of Protestantism and defender of a British Protestant monarch. It is organised into “lodges”, some of which are in former British colonies further away.
On July 11th, “Eleventh Night” bonfires are lit in staunchly Protestant localities. Many are huge constructions of wooden pallets. At midnight the bonfires are set alight, and can be seen burning across Belfast.
Members of the nationalist, often Catholic, community have for years voiced their disquiet over what they see as provocative, sectarian marches proceeding through their neighbourhoods.
Many parades in the past have lead to rioting by both sides of the divide.