When Arsène Wenger arrived at Highbury in September 1996, Arsenal's fans wondered who on earth he was. Now they wouldn't swap him for anyone.
A virtual unknown in English football, Wenger had much to prove when he moved from Japan to North London. But if any doubts lingered over his appointment, the Frenchman soon dispelled them.
As his players soon realised, Wenger was a different breed of manager. The old-school habits of throwing teacups and tantrums were not for him. Instead the squad grew accustomed to nutrition and new training methods. Off the pitch Wenger has been just as effective, taking an active role in the building of a new training ground and the Emirates Stadium project.
Results on the pitch vindicated the new man in charge. Wenger won the Double in his first full season in charge and almost repeated the feat a year later. A couple of agonising Cup Final defeats followed but Wenger doubled up again in 2002, clinching the title at Old Trafford.
A second successive FA Cup triumph followed in 2003 and then perhaps Wenger's greatest achievement, leading his team to an unbeaten title season and, ultimately, a league record of 49 games without defeat. Yet another FA Cup win followed in 2005 as the Frenchman continued to rack up the trophies.
But Wenger has always been about more than results and trophies. He has transformed relative unknowns into world-class stars - Vieira, Petit, Anelka, Ljungberg and Fabregas for example. And he will always be remembered for turning Thierry Henry from a talented winger into a superstar striker.
But perhaps Wenger's greatest legacy will be the style with which he has brought success. Many clubs have won trophies, but few have managed it with the panache of Arsène's Arsenal. In September 1996 it was a case of 'Arsène Who?' These days, Wenger ranks alongside Herbert Chapman as Arsenal's greatest manager.