Catholics and Protestants have found cause to fight each other ever since Martin Luther supposedly started criticising the Catholic Church in the 16th century.

One of the most virulent examples of this inter-faith fighting were the 'troubles' during which more than 3,600 people were killed. However when the Irish rugby team walk out to play Argentina in their world cup quarter-final on Sunday afternoon, both Catholics and Protestants will stand together to cheer on their team.

Ireland's rugby team has always been united. Unlike football, where Northern Ireland and the Republic of Ireland field separate teams or other sports where Northern Irish players often choose to represent Britain rather than Ireland, rugby has always fielded a unified side.

One key aspect is that Ireland's rugby team has always included players from the Northern Irish club Ulster alongside players from Leinster, Munster and Connacht.

"Rugby is looked at as more of a family thing," one supporter told Reuters.

"There is no community difference in rugby. Ulster rugby players playing for Ireland is the most intertwining factor. It is a positive that they come together," he said.

However rugby did not remain immune from the troubles. Shortly before the inaugural rugby world cup in 1987, three Northern-Irish born players were travelling to training when the car next to them was blown up the Irish Republican Army (IRA). Although they were not the targets, one was injured and forced to retire.

"When I started, I remember we had Special Branch (police) guys with guns standing on the side of the training sessions," said former Ireland player Keith Wood, who captained the team from 1996 to 2003.

"Things have thankfully moved on an awful lot. There is still a long way for that to go but if rugby can be of any additional benefit to that process, isn't that a great side effect to having a Rugby World Cup bid," Wood told Reuters.

Ireland are alongside France, Italy and South Africa as potential hosts for the 2023 rugby world cup.

However at the same time as Ireland's rugby team seems to be a beacon of unity and religious tolerance, Northern Ireland's politicians are demonstrating the ugliest aspects of sectarianism.

After a former IRA leader was shot in Belfast, George Hamilton, Northern Ireland's Chief Constable concluded individual IRA members were behind the killing. However the response of Protestant based Unionists parties has partial withdrawal from the assembly. Business cannot continue if the IRA still exists, said Northern Ireland's First Minister, Peter Robinson.

Both sides are playing childish politics and are creating a political limbo that is not good for the assembly's reputation nor ongoing cross party relations.

Although neither side want the collapse of the assembly and moderates on both sides are hoping a deal can be reached, it is an unnecessary blip on the path to lasting peace.

When Ireland and Argentina do battle on Sunday afternoon, their fans at the Millennium Stadium in Cardiff will represent one of the great success stories in religious conflict reconciliation. Lets hope their so-called political leaders can learn from the rugby team's example.

Additional reporting from Reuters.