Over the years, the importance of an assistant manager has been downplayed and revered in equal measure. The Boot Room at Liverpool and Brian Clough’s erstwhile number two Peter Taylor are often held up as prime examples of the crucial role backroom staff play in the success of a team.

Sir Alex Ferguson had a plethora of assistants during his time at Old Trafford, the managerial legend picking ambitious and talented number twos who longed for a chance in the big chair. Ferguson was not one to stand in their way and, just as the coaching culture of the NFL does, he took great pride in them making the step up to become managers themselves.

The clash and subsequent fall out between Clough and Taylor has been etched in football folklore, a source of regret that Clough took to the grave. Taylor jumped at the opportunity to become his own man, much to the chagrin of Clough who had become so accustomed to having Taylor as his confidante and sounding board that he felt betrayed when his once close friend, having chosen to step out of the shadows, failed to inform Clough he was trying to sign one of his players. They were never as successful apart as they were together and the duo’s rift remained unhealed at the time of Taylor’s death in 1990.

While Jock Stein rightfully received many plaudits for what he achieved at Celtic, it is noted in the east end of Glasgow how none of it would have been possible without the impact of his number two, Sean Fallon – a partnership that provided the club’s greatest achievement and produced teams packed with some of the best players to ever pull on the green and white shirt. The brusque Scot and the influential Irishman complimented each other to perfection, both realising the importance of each other in achieving a common goal.

All of this was a million miles away for a young Fallon, one of nine children, born in Sligo during the summer of 1922. His father, John, along with 200,000 other Irishmen left their homes to fight in World War One during what was a tumultuous time in the country. The Easter Rising of 1916 saw a group of Irish nationalists proclaim the establishment of the Irish Republic and stage a rebellion against the British government. The subsequent clashes with British troops saw almost 500 people killed and over 2,500 wounded.

It was while recuperating in Glasgow during the war that John Fallon became aware of the Celtic Football Club. It had been founded by Brother Walfrid, a Marist priest in 1888 as a charity to help raise money for the poor in the deprived east of the city, Walfrid himself having arrived in Glasgow from Sligo.

Upon Fallon’s return home, he regaled his family with tales of the priest’s good work and the club he had founded. Sean’s interest was piqued, and when his sister was saved from drowning by the son of Celtic legend Jimmy McMenemy, it grew even more. After the heroic deed, both families became acquainted and Joe McMenemy told the already intrigued Fallon more tales of Celtic, sending him a club shirt and book upon his return home. From this moment on, there was only one club that the football-mad Fallon wanted to play for.

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Despite his interest in football, it was swimming that Fallon found himself a natural at. His ability, combined with a tremendous work ethic, meant he would have made a top-level triathlete at the time. On leaving school, he worked at a local bakery and, despite the early start, would find time to go running and take a swim off Rosses Point.

Gaelic football was the game of choice for many at the time. Fallon was no different and combined both that and football. During a game of Gaelic football for Sligo, he scored past one of the game’s great goalkeepers, Dan O’Keefe. A picture of Fallon made the local press, where he happened to be wearing a football shirt. At the time there was a ban on playing what was deemed a “foreign” sport – and Fallon was given the ultimatum of choosing between one form of football.

Never one to back down, Fallon refused and said goodbye to the native game to concentrate on the round ball. He turned out in a regional Irish league before Sligo Rovers offered him the chance to play senior football. His performances for The Bit o’ Red didn’t go unnoticed and it wasn’t long before professional Northern Ireland club Glenavon came calling and took him away from Sligo.

The move to the Lurgan Blues in 1949 finally saw Fallon become a full-time footballer at the age of 27. The full-back had an immediate impact with his new club and was named to represent the Irish League in a game against a League of Ireland XI. Celtic scout Peter O’Connor was watching on and was so impressed by Fallon that he recommended him to manager Jimmy McGrory, who followed up the suggestion by making the trip to Mourneview Park to see for himself.

Equally enamoured, McGrory offered Fallon the chance to play for Celtic. The 28-year old flew into a panic, convinced that if McGrory knew his age he may have been deemed too old and that the move would fall through. Fallon provided his passport details to the club for his registration had changed his date of birth, shaving six years off his age in the process.

The move was finalised and Fallon realised his dream. Incredibly, Celtic thought they were getting themselves a 22-year old left-back, still years away from his peak. It was at Celtic Park that Fallon got his nickname Iron Man; tough and determined, he never shirked out of a challenge. Despite suffering five arm breaks, torn ligaments to his knees and ankles, and many other broken bones, he never failed to finish a match.

Being physical was part of Fallon’s game; he was tough, brave and gave 100 percent without being dirty. He was on the receiving end of a vicious assault whilst playing against Clyde, their renowned hard man Sammy Baird kicking Fallon in the head whilst he was prone on the floor. Not one to retaliate, Fallon bided his time and when Baird moved to Rangers, they lined-up against each other in an Old Firm game.

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Baird was a pantomime villain hated by opposition fans, and when he and Fallon contested a 50-50, there was only going to be one outcome. Remembering the cowardly act from before, Fallon put everything he had into the tackle, crunching Baird, breaking his collar bone and shoulder in the process. Fallon visited the hospitalised hatchet man after the game and there were no hard feelings between the two, Baird clearly able to take the same punishment that he dished out.

His first silverware at Celtic came in his second season during a victory over Motherwell in the Scottish Cup final. However, the following seasons saw Celtic languishing in the league and a player arrived who was far from the answer the Parkhead faithful had been looking for.

Jock Stein had been playing for Llanelli in the Welsh non-league when he was brought to the club in the twilight of his career. He slotted in at centre half and immediately hit it off with Fallon who ironically, given the fans’ unhappiness to Stein’s age, was actually older than the new signing. Fallon was made captain in 1953 and immediately made Stein his second-in-charge.

The 1953/54 season looked promising for the Bhoys yet injury struck Fallon again. This time a broken collar bone brought an end to his participation so he headed home to Sligo to recover. Missing the game, he returned to Glasgow in a watching brief, but when striker John McPhail went down with an injury, it was desperate times for Celtic with a very limited squad.

Hearts had an eight-point lead at the top of the table, and in the days of two points for a win, the lead looked unassailable. Fallon returned to be deployed as a makeshift striker and set off on a scoring streak that saw Celtic enjoy seven consecutive wins and overhaul the Jam Tarts to win the league title.

The unlikely comeback gave Celtic the opportunity to capture their first league and cup double in 40 years when they then went on to face Aberdeen in the Scottish Cup final. Over 130,000 people crammed into Hampden Park on a blisteringly hot day; amongst them Fallon’s father who had made the trip from Sligo to watch his son.

It was Fallon who scored the decisive goal in a 2-1 win, slotting home from eight yards to send the east end of Glasgow into rapture. It was a result that would only be bettered four years later when Rangers were hammered 7-1 in the League Cup final, the most lopsided result in a Scottish cup final.

Fallon was named in the team of the year, however, only three months after receiving this accolade, he had to call time on his career, a chronic knee injury bringing proceedings to a close at the age of 35. The initial worries Fallon had about his age when he signed for Celtic proved unfounded as he played for eight years and appeared in 254 games.

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Fallon had suffering homesickness throughout his time in Scotland and many expected him to return to Sligo, where his father was mayor, now that his playing career had finished. However, by chance, teammate Billy Craig invited him to a party where Fallon met his future wife Myra. Suddenly he had someone to stay in Scotland for. Chairman Bob Kelly saw him as the ideal successor to McGrory, offering him a place on the coaching staff.

McGrory was the manager in name alone; Kelly picked the team and was also in charge of the club’s transfer dealings. He became obsessed with replicating the Busby Babes of Manchester United, with the early 1960s seeing many experienced players leave the club and replaced by youngsters perhaps given their chance too soon.

This was a difficult time for Celtic. Fallon was being groomed as the heir apparent but when the axe fell on McGrory in 1965, he was overlooked. The man who Fallon nominated to replace him as captain, Jock Stein, returned to the club following successful spells in charge at Dunfermline and Hibernian. Whilst many would have seen this as a slight on them, Fallon’s love for the club meant he showed no resentment. He stayed as Stein’s assistant and, unbeknownst to the new manager, his number two was about to unveil the keys to their future success.

A significant part of Fallon’s role as assistant was finding young talent from the bustling streets of Glasgow. His talent at spotting and developing players had become his speciality and, on Stein’s arrival, he was about to unleash 10 of the 11 Lisbon Lions on the game. The ability to pick out a diamond in the rough was not just limited to youngsters: he convinced then-Hibs manager Stein to part with ageing goalkeeper Ronnie Simpson, bartering the price down having convinced his old teammate he was only needed as a reserve.

His powers of persuasion were legendary. With Kelly adamant the future lay in youth, Fallon had to convince McGrory that Simpson would bring much-needed know-how to a youthful team. The custodian would go on to make over 200 appearances for the Bhoys and was named Scottish Player of the Year in 1967.

Fallon also pleaded the case to re-sign Bertie Auld from Birmingham, the cocksure midfielder seen as another missing piece of the puzzle. With the team virtually assembled upon Stein’s arrival, Fallon also fought the corner of diminutive winger Jimmy Johnstone, with the manager not initially convinced by him.

The combination of Fallon’s eye for talent and Stein’s tactical nous made them the perfect management team. Each man filled the other’s gaps in expertise. The culmination of Celtic’s epic European journey in 1967 was a date with Helenio Herrera’s Internazionale in Lisbon for the final of the European Cup, made up of a team from within a 30-mile radius of Parkhead.

Read | The miner and the migrant: how Jock Stein and Helenio Herrera created a rivalry fit for the ages

The Bhoys’ chances were slim yet they came out on top in a 2-1 win, the scoreline flattering the Italian’s who, without the heroics of goalkeeper Giuliano Sarti, would have been hammered out of sight. As the travelling masses descended onto the pitch at full-time, it was up to Fallon to barge captain Billy McNeill through the joyous Celtic fans to lift the trophy.

Meanwhile, back in Glasgow, Fallon was already building another team of young starlets that some believed could go on to emulate the Lisbon Lions. Named the Quality Street Gang by the Glasgow media, Celtic’s reserves were so rampant that Stein inquired about entering them into the lower leagues of the professional game. It was a request that was denied but has been repeated in recent times by the likes of Pep Guardiola.

Lou Macari, David Hay and Danny McGrain all went on to have successful careers, whilst other members of the gang like George Connelly and Tony McBride tragically failed to live up to their early promise. The star of the side was a young man whose family’s flat was within a goal-kick’s distance of Ibrox, who spent his formative years as a Rangers supporter.

So special was the youngster named Kenny Dalglish that Fallon stopped off at his home on the way to taking his family out for a wedding anniversary meal. Fallon persuaded Dalglish to sign and he would go on to have a huge impact in the British game, controversially leaving Celtic for Liverpool as the chairman began to sell off their prized jewels.

Stein was injured in a 1975 car accident that saw Fallon step into the breach as temporary manager. When the legendary manager eventually departed Parkhead, Fallon was yet again overlooked, with McNeill taking over. Fallon too bid farewell and became assistant manager at Dumbarton in 1978 before finally getting his chance at the top job two years later. He stepped down in 1981 and retired from the game.

A new generation of fans who grew up on tales of the Lisbon Lions may not have known the effect that Fallon had on that team’s success when he was invited to unfurl a league winners banner at Celtic Park – but his name would quickly echo around the ground again. He passed away aged 90 in 2013, his reputation for finding, nurturing and developing some of the greatest players to grace Scotland’s game firmly intact.

Some time ago, Celtic fans were asked to pick their team of the century. Over half of the chosen players were discovered by Sean Fallon – a humble servant to a club whose eye for spotting talent may never be rivalled.

By Matthew Evans @Matt_The_Met