On a cold overcast New Year's Day in 1957 an IRA unit launched an ill-fated attack on an RUC barracks, sparking a bloody battle that has reached almost mythological status in Irish history.
Limerick man Sean South (28) and 20-year-old Fergal O'Hanlon, from Monaghan, had been members of the 14-strong IRA unit, led by Sean Garland, that set out that morning in an attempt to storm the Brookeborough RUC barracks in the Co Fermanagh village.
The assault had been planned as part of Operation Harvest the IRA's Border Campaign between 1956 and 1962, which intended that flying columns would cross the border from the Republic and attack military and infrastructure targets within Northern Ireland.
An IRA document found in 1956 stated that the aim of the campaign was to "break down the enemy's administration in the occupied area until he is forced to withdraw his forces".
IRA members had travelled from as far afield as Cork, Dublin, Wexford, Galway and Limerick to take part in the New Year's Day assault. But their plan to bomb the barracks went dramatically wrong.
In his book Sean South of Garryowen, author Des Fogerty says that about a week earlier the RUC had received intelligence that a border station would be attacked. Officers at Brookeborough were well-armed while the station had been sandbagged and equipped with a radio telephone to call for reinforcements if needed. The fateful gun battle began within seconds of an RUC officer discovering by chance the IRA man Phil O'Donoghue attempting to lay a bomb at the barracks door. Two devices failed to detonate and a grenade bounced off the barracks and injured O'Donoghue instead.
Seven men were injured in the attack. Five would survive but Sean South had received a fatal wound to the lower back while Fergal O'Hanlon was bleeding badly after being struck in the legs.
The unit fled the scene, taking temporary shelter in a cowhouse where O' Hanlon lay dying. It is likely that South was already dead.
The survivors eventually managed to make their way back across the border to a farmhouse.
The wounded were later taken to hospital while the others were arrested.
An inquest would find that South had been beyond help when the unit had entered the cowhouse but that O'Hanlon's life could have been saved by first aid a finding that has been disputed over the decades.
Sean South had lived a quiet but industrious life with his mother and two brothers in Limerick before the raid.
His brother Ger, aged 21 at the time of the Brookeborough attack, recalls how the killing of the man they had known as a hard-working timber yard clerk, scout leader and Irish-language enthusiast had a lasting effect on the family.
"We had all been unaware of the depth of his involvement in the IRA at the time," Ger South said.
"We first learned of what was happening shortly after he went to the north and used me as a conduit for communicating with the family. We realised that he had been working away while training with the IRA in the mid-west.
"We'll never be fully sure what motivated him to take the line he did. We lived together. We slept in the same bed. We were very close. But when he was away from here nobody would know where he was. He was obviously out training.
"He'd always loved books and would buy some every week when he got his wages.
"It was after his death that we looked at what he'd been reading and got some insight into what he was thinking.
"There were books on economics, how wealth was dispersed in society, the Irish language and Irish organisations."
Ger South remembers that his brother had "seen a lot of life" in the years before his death. He had joined the FCA (An Forsa Cosanta Aitiuil or army reserve) and An Rialt, an Irish-speaking wing of the Legion of Mary. As a scout leader, he had encouraged local youths to speak Irish.
"But after Sean died there were a lot of changes. Our house had always been full of chat and craic but my mother Mary refused to live there and we moved to a corporation flat. There were too many memories."
Over the decades, Ger South has heard "all strands of the republican movement" claim they would have had his brother's support.
He remains convinced Sean would not have taken his decision to join the IRA lightly.
"He would never do anything in a foolish or haphazard way," he said.
"Everything was thought through. He obviously had studied [the situation in the north] to the extent he felt it was the only thing to do. It annoys me when people think they know what he would or would not want today."
Fergal O'Hanlon had worked as a clerk and local authority draughtsman. He spent his spare time going to dances and playing Gaelic football and handball in his native Monaghan.
His sister Padraigin Ui Mhurchadha, aged 15 at the time of his death, describes him as a "wonderful son and brother" who had many friends and was "great to everybody in the family".
While the South family had been taken by surprise at news of Sean's IRA activities, the O'Hanlons had been been brought up in a "very republican house".
"He would have grown up with Irish as his first language. We lived in a border county so we were very aware about what was happening in the six counties. We knew that Catholics were enduring terrible intimidation and suffering.
"Although I was young and it wouldn't really have been discussed in front of me, I would have sensed that Fergal was involved in the [border campaign] but we believe [Brookeborough] was his first military activity."
Ms Ui Mhurchadha, a Sinn Féin Monaghan town councillor, had been visiting a relative's house when the radio reported that two men had been killed in the north.
"We had known Fergal was away because he had said goodbye to us all. He had taken his leave of my mother Alice and when we heard the news she felt straight away he had been killed.
"The next morning we were asked by the gardai to go to Monaghan Hospital and were told by the men being treated there that Fergal was dead.
"I remember all the sounds the knock on the door by the guards, Daddy telling Mammy, her crying.
"He was a month off 21. We were very proud of Fergal. He had been fighting for Ireland but we were heartbroken when he died.
"We received many many visitors, letters and telegrams of support. It was incredible. Thousands attended the funeral. Fergal and Sean's deaths had caught the imagination of the whole country."
However, for the unionist community, the men had simply been "terrorists who had attacked us and were caught in a gun battle".
Retired Fermanagh Ulster Unionist Party MLA Sam Foster was a member of the Ulster Special Constabulary in 1957, assisting the RUC in patrols and searches.
"It was a very watchful time, patrolling the area during what was regarded as a terrorist campaign. We got a bad name but I was in the force for 20 years and I never gave offence to anyone. I just did my duty. We were there to guard the province. We contended we were British and that was our right.
"Obviously, the station [in Brookeborough] was in the centre of a village and it had to be defended and that was how South and O'Hanlon got killed."
Crowds lined the route to the border to pay a final tribute to South and O'Hanlon as their bodies were carried from Enniskillen to the cathedral in Monaghan, where they lay in state overnight. Thousands more attended the funerals in Monaghan and Limerick.