Both the unionist and nationalist cultures have strong traditions of holding parades and rallies, but the Protestants have shown a particular appetite for taking to the streets.
The marching season is not now just an adjunct to unionism, but a central part of it.
When serious disorder broke out six times in Ulster between 1857 and 1886, the reports of all six commissions of inquiry blamed two main factors - poor policing and Orange parades.
One of the reports said the [July 12] occasion was used "to remind one party of the triumph of their ancestors over those of the other, and to inculcate the feelings of Protestant superiority over their Roman Catholic neighbours". July 12 is the date William of Orange won the Battle of the Boyne.
The strength of feeling the marching season generates on both sides is difficult for outsiders to comprehend.
In 1920, a London newspaper said: "The thrill which the genuine Orangeman finds in those demonstrations cannot be communicated to the most impressionable stranger, however devoted he may be to the British Empire.
"The relief which Ulster still feels at the liberation bought on the Boyne 230 years ago is unfathomable to an outsider; but these things are all very real to Orangemen."
The Sixties saw Catholics taking to the streets for civil rights marches on the model of those led in the US by Martin Luther King.
But within a short space of time, loyalist counter-demonstrations appeared and there were ugly clashes.
It was a unionist Apprentice Boys' march in the city of Londonderry in August 1969 which resulted in the widespread disorder that led to the deployment of British troops on the streets of Northern Ireland.
Since then, marches and parades have periodically been the occasion of disturbances.
Northern Ireland hosts around 3,500 marches a year. Around 600 have no political or sectarian overtones. About 300 are organised by nationalists and republicans. The majority of marches are staged by loyalist groupings, principally the Orange Order.
Recent statistics have shown that the number of loyalist parades has risen steeply, going up by almost a third over the past decade. Virtually all of these take place in what is called the marching season, which lasts from Easter to September, reaching high points in mid-July and mid-August. The vast majority of these pass off peacefully, but each year a small number generate controversy and sometimes violence.
The two principal flashpoints in recent years have become Drumcree at Portadown, Co Armagh, and the Lower Ormeau Rd, south Belfast.
Both of these are primarily Catholic enclaves surrounded by Protestant areas. In both cases, Catholic protests mean that the marchers are accompanied by a strong police presence.
The clash of perspectives between the Protestant marchers and the Catholic residents was summarised in a recent report by academics Neil Jarman and Dominic Bryan.
"Each parade which is challenged is a symbolic threat to Protestant security and the Unionist position," noted the report, "while each parade which passes through a nationalist area is a restatement of the dominance of the Protestant community and the inferiority of nationalist rights."
While such parades increase local tensions, they are often at their most dangerous when they assume a wider political significance.
Some of the most violent clashes came in the mid-Eighties as loyalists protested against the Anglo-Irish agreement.
Last year in Portadown, 800 marchers were allowed to pass through the Catholic district after three-day stand-off between the Orangemen and the RUC. This was seen as a major victory by the Orange Order. "Siege of Drumcree" medals were later awarded to the Rev Ian Paisley and David Trimble.
In Northern Ireland, July is, at the best of times, a month associated with a general rise in nervous tension.
But a "bad" marching season can sour the atmosphere, play on the most sensitive nerve-endings of the two communities and seriously damage the prospects for political progress.