Sir Alex Ferguson will retire as Manchester United manager at the end of the season and become a director and club ambassador. Here, Press Association Sport's Andy Hampson looks at the toughest tests of his Old Trafford reign.
Early survival and establishing himself
Ferguson may have had a strong reputation in Scotland when he arrived but that would not have saved him had the troubles of his first few seasons continued much longer. United flirted with relegation in 1989-90 but crucially kept the season alive by shining in the FA Cup. They went on to win the trophy with victory over Crystal Palace in a replayed final and Ferguson's reign gathered momentum.
Reclaiming the league title
United had enjoyed occasional cup successes since last winning the league in 1967 but they were largely living off past glories until Ferguson finally ended their title drought. In 1991-92 they made a strong challenge only to lose out to Leeds at the last hurdle. There was no mistake 12 months later, however, and a further 11 titles have since followed.
Winning the Champions League
With a 26-year league hoodoo broken, United's 'holy grail' became success in Europe's elite competition. Admittedly rules regarding foreign players were a hindrance, but mid-1990s European challenges were characterised by struggles and disappointing defeats to teams such as Galatasaray, IFK Gothenburg and Fenerbahce - as well as one infamous footballing lesson from Barcelona. Ferguson ensured they were a far tougher outfit by the end of the decade, though, and they finally threw the monkey off their back in 1999, when victory over Bayern Munich in Barcelona completed a glorious treble.
Rebuilding the team
To maintain his phenomenal success, Ferguson has continually regenerated his team. Arguably he never did this better than after his initial flurry of trophies when the likes of Paul Ince, Mark Hughes and Andrei Kanchelskis moved on. Ferguson put faith in youngsters such as David Beckham, Nicky Butt and Paul Scholes and was derided for doing so, but it paid off handsomely. Similarly after Arsenal and Chelsea shared the titles from 2004-06, Ferguson hit back with a new side built around Cristiano Ronaldo and Wayne Rooney.
Dealing with player power
The rise of player power over the past two decades has given managers at many clubs huge problems, but Ferguson rarely bows to it. He is very much the boss at Old Trafford and his position is virtually untouchable. There have been controversies involving big-name players including David Beckham, Roy Keane, Jaap Stam and Paul Ince but Ferguson has not only won each time, but been proved right. Last year Rooney appeared to burn bridges in dramatic fashion but he was coaxed back into the fold, and with remarkable results.
Silencing the noisy neighbours
When Manchester City, backed by the seemingly endless wealth of Sheikh Mansour, became champions of England last season for the first time in 44 years, it seemed the power balance in the city may have shifted indefinitely. But while Roberto Mancini's men struggled to recreate the football that took the Premier League trophy to Eastlands, Ferguson made another key signing - bringing in Robin van Persie from rivals Arsenal - and took title number 13 to Old Trafford to quieten City down for another season.