Thousands of people are taking part in commemoration celebrations in Belfast to mark one of the most significant dates in the history of Northern Ireland.
On Saturday, police across Northern Ireland were out in force in case of trouble during Protestant Loyalist parades.
There are fears that the protests might degenerate into street clashes with the police and Northern Ireland's Catholic minority, who are mounting counter demonstrations in protest.
The six-mile march from central Belfast to Stormont will mark the 100th anniversary of the Ulster Covenant, to oppose Home Rule for Ireland in 1912.
The covenant signing of the document laid the foundations for the partition of Ireland and the formation of Northern Ireland a decade later.
There was no trouble at a contentious feeder parade past a north Belfast Catholic church on Saturday morning.
The Parades Commission has ruled that only hymn music is to be played as bands pass the church and has limited any nationalist protest to 150 people.
Al Jazeera's Laurence Lee, reporting from Belfast, said: "This day for the Protestants see it as a celebration, while the Catholics see this day as a catasrophe."
"These marches are used by sections of the protestant communities to wind up the Catholics," the Al Jazeera correspondent said.
Nearly two decades of peacemaking have transformed Northern Ireland almost beyond recognition from its blood-stained past.
Since 1998 there has been various paramilitary cease-fires by the IRA and Protestant groupsm which has been underpinned by disarmament, with troops being withdrawn to their barracks.
Power sharing executive has been in place since 2007, while the United Kingdom has promoted Catholic recruitment to create a balanced police force as well.