It is part of our history that was buried during the Northern Troubles. For centuries, tens of thousands of Irish soldiers travelled the world fighting for the British Army.
They carried the standard at Waterloo, and landed on the Normandy shore on D-day.
They were proud of their Irish heritage, marching with their Irish regiments on St Patrick's Day, but they still had a yearning to fight for Queen and country.
It is a tradition that is being revived. The British Army reports a surge in the number of recruits from the Republic.
A growing number of young Irishmen are travelling across the border to join up, frequently ending up in Iraq and Afghanistan at a young age.
It may be enough to make a Sinn Feiner weep, but the Poppy -- sold to raise money to benefit ex-servicemen from the British forces -- is becoming an accepted part of the Irish tradition.
Sales of Poppies have increased by almost 50pc in the Republic over the past year, a sure sign that hostility to the British Army is diminishing.
Episodes such as Bloody Sunday, when 13 innocent civilians were shot dead in Derry, stoked an understandable hatred of the British uniform for generations, deterring many Irish from joining up.
But in a sign of the changing relationship between Britain and Ireland, brought by the end of Operation Banner and the Troubles, recruiters in Northern Ireland have revealed that 16pc of all those enlisting since April of this year are from the South.
That figure is up from 10.5pc last year, which was in itself more than double for 2006. Rather than deterring recruits, the wars in Iraq and Afghanistan seem to have encouraged them.
Even in the darkest hours of the Troubles, Ireland's British Army tradition continued, of course, but the soldiers had to keep their vocation secret.
When Sergeant Major Robbie O'Farrell from Bunclody in Co Wexford joined up in 1987, he did not tell anybody but his closest family and a couple of friends.
"I joined straight from school. For security reasons it was not something that you talked about openly, but that has changed."
Robbie O'Farrell said he felt he could be much more open about his involvement in the army after the funeral of Dubliner Lance Corporal Ian Malone in 2003.
Malone, from Ballyfermot, was killed in an ambush by sniper fire near Basra at the start of the Iraq war.
Robbie O'Farrell said: "He was given a military funeral (attended by representatives of the Irish and British armies in Dublin), and there was a good turn-out. It was then that I realised that the mood back home was very different.
"When I talk to people in Ireland about being in the army they are mostly intrigued."
As a member of the Royal Irish Regiment, Robbie O'Farrell is a hugely-experienced soldier, who has served in Iraq, Kosovo and Northern Ireland. He has recently returned from Afghanistan, where he narrowly escaped death from a suicide bomb.
"There was a car bomb that went off just near us, and fortunately only one of the guys got minor injuries."
So what motivates these soldiers to cross borders to join a foreign army?
Captain Stevie Swan (28) from Howth, Co Dublin, said he trained to become an officer at Sandhurst (where Princes William and Harry also trained) after meeting English friends who were joining the British army.
'I think many Irish soldiers apply to join the British army because they see it as a highly professional force," says the Business studies graduate. "Because Ireland is neutral, you might not have the same opportunities in the Irish army.
"I was quite worried about how people would react when I joined, and I wondered whether I should tell people. But the reaction in Ireland has been very positive. People are fascinated.
"Since I have joined I have met four other guys from Howth who are in the army. I am very proud of the work that we do."
Some of the recruits to the British army may have applied to the Irish army, but were turned down.
The involvement of Irish soldiers has not come without a cost in lives. As well as the death of Lance Corporal Malone in Iraq, 29-year-old Ranger Justin Cupples from Cavan was killed when a Taliban bomb exploded last month.
The commander of the first battalion of the Royal Irish Regiment, Lieutenant Col Ed Freely, believes the soldiers from the South are an essential part of the regiment.
"I think they stand out for their commitment and quality."
He sees the Royal Irish as a "pan-Irish" regiment, with troops from Northern Ireland, the Republic and elsewhere.
The regiment celebrates its Irish traditions to an extent that is not always apparent in the South.
The motto is "Fag an bealach" (Clear the way), the mascot is an Irish wolfhound, and the insignia includes a shamrock.
"St Patrick's Day is our big day," Commander Ed Freely says. "We have a parade. There is a strong tradition of Irish music in the regiment, and we have Irish dancing."
With its recent track record in Northern Ireland, Afghanistan, Iraq and the Balkans, the regiment is now one of the m ost experienced fighting forces in the world.
"I believe that because of its Irish tradition the regiment is suited to the needs of modern warfare. They have the right temperament and show sensitivity in co-operating with local populations."
The Irish in the British army may now be much more open about their activities, encountering positive curiosity when they return home.
But there is still some opposition. A recent letter writer to The Irish Times suggested that the description of British Army recruits as "Irish soldiers" in a report was "an affront to those who fought, many making the ultimate sacrifice, to free this country from British rule".
This view may now be in the minority, however.
"If you look into it you will find that most Irish families have some roots in the British Army," says Pam Roche, administrator of the Royal British Legion in Ireland.
"The Legion sells Poppies at this time of year, with the money going to help veterans and their families.
"TV programmes such Who Do You Think You Are?, which showed Joe Duffy's antecedents in the British Army in India, have helped to change attitudes. There is a great desire to acknowledge that this is part of Irish tradition."