Tens of thousands of pro-British unionists marched through Belfast on Saturday to mark 100 years since a landmark event in the history of Ireland's partition.
An estimated 30,000 people joined the parade to commemorate the centenary of the Ulster Covenant, a landmark declaration signed by nearly half a million Protestants who vowed to defend themselves against rule from Dublin.
The covenant laid the foundations for the partition of Ireland and the creation of Northern Ireland as a British province in 1921.
The march -- one of the biggest loyalist parades ever held in Belfast -- passed off peacefully despite fears of clashes with the Catholic minority.
The Police Service of Northern Ireland (PSNI) mounted its biggest operation in 20 years for the march, the BBC reported.
"Today there's been an overwhelming mood of dignity and respect and enjoyment and mutual co-operation," the force's Chief Constable Matt Baggott told the broadcaster.
The six-mile (10-kilometre) march set off from central Belfast just after 10:00 am (0900 GMT) and headed east towards a cultural festival being held in the grounds of Northern Ireland's parliament at Stormont.
The parade finished at 6:00 pm.
For Protestants, the marches -- in which participants wave banners and bands play traditional music -- are an important expression of Northern Ireland's continued union with Britain, but Catholics see them as intimidating.
Under a heavy police presence, the march passed a Catholic church in north Belfast that had been seen as a potential flashpoint after it was the scene of sectarian scuffles last month.
Marchers had agreed to sing only hymns as they passed St Patrick's Church, refraining from singing any sectarian songs.
But some residents said bands defied the agreement and played the most famous Unionist anthem, "The Sash", before reaching the end of the stretch outside the church.
"Some of the bands, yes, they did stick by it, there's no problem there," said Frank Dempsey, chairman of the local Carrick Hill Residents Association.
"But a number of them bands broke that."
Belfast suffered three nights of rioting earlier this month, in which more than 60 police officers were injured, after Protestants tried to disrupt a march by Catholic republicans.
Around 3,500 people died in the three decades of sectarian violence between Northern Ireland's Catholics and Protestants that largely ended with a 1998 peace agreement, though sporadic unrest and bomb threats continue.