
When Arsenal sacked Bruce Rioch in the summer of 1996, the first name on everyone's lips as the potential successor was the legendary Johan Cruyff.

It proved a non-starter, Cruyff didn't want a manager's job at the time and in any case Arsenal's most influential director David Dein had set his eyes on a largely unknown Frenchman who was working in Japan, Arsene Wenger.

The reaction when news finally leaked that Wenger would be given the keys to one of England's great traditional football club was astonishment. 'Arsene Who?' was the general reaction. Little did they know the club were appointing the most influential coach and manager the world has seen since Cruyff himself.

Arsene Wenger on the touchline before kick-off in Arsenal's EFL Cup third round match against Nottingham Forest

The Frenchman was unveiled on the pitch of Arsenal's old Highbury Stadium 20 years ago back in 1996

He has not won the amount of trophies that Sir Alex Ferguson collected or the European triumphs of a Jose Mourinho, Pep Guardiola or Carlo Ancelotti, but in 20 years he has revolutionised English football. And English football being the market leader for any club football, the impact has been astounding.

Technical, passing, possession football is now the norm for teams who want to be regarded as world contenders. Not when Arsene arrived, it was his blueprint that made it so.

Diet and fitness were still seen as relatively inconsequential compared to team spirit usually fostered by mammoth boozing sessions.

Wenger came in, banned Mars Bars, gave his players supplements and watched the victories and trophies roll in. No leading manager today works without a battery of sports scientists and analysts at his disposal.

Wenger started it, and the idea that young overseas players could come to England in their formative years and thrive. Pre-Wenger, there was scepticism that foreign managers would be able to 'get' English football let alone foreign youngsters who were brought up by passing the ball rather than running up and down sand dunes at Blackpool beach to aid fitness.

Nicolas Anelka, Patrick Vieira and later Cesc Fabregas came, saw and conquered. Again, every big club academy scouts the world for talent these days.

Wenger sits in the middle of the team photo for Arsenal's 2016-17 season and his 21st campaign in charge at the club

Of course, that policy has its drawbacks, particularly for young local players but nonetheless Wenger was a pioneer.

And he has been successful. Four clubs have won the Premier League more than once. Manchester United had the advantage of being a genuine global phenomenon with supporters in all four corners of the planet. Manchester City and Chelsea had the advantage of unprecedented financial support.

Arsenal are the only self-made members of that 'Big Four.' Without Wenger, it is entirely probable, let alone possible, that the Gunners would not be the force they are today, even with their great tradition.

In the four Premier League seasons before Wenger arrived, Arsenal finished 10th , fourth, 12th and fifth. For the last three of those years, they lagged behind Newcastle United but since then they've not been outside of the top four.

Critics will point to the lack of trophies in the second half of Wenger's two decades. And they'd be right up to a point. But as success is relative – England manager Sam Allardyce was widely backed for the post despite never having won a trophy – failure is relative too.

Wenger lifts up the Premier League trophy alongside former captain Patrick Vieira outside Islington Town Hall in May 2004

If Wenger is a failure for always finishing inside the top four, that's nowhere near as big a failure as other so-called big clubs. Everton haven't won a trophy since 1995, Liverpool haven't won a title since 1990 and Tottenham since the early 1960s.

Every other club - Chelsea, Manchester United, Liverpool and Manchester City - have spent time outside the Champions League. Arsenal haven't under Wenger.

Why has Wenger been such a huge success? Certainly, he was lucky in two respects when he took over at Arsenal.

Firstly, his ideas on conditioning, talent-spotting and how to play the game were viewed suspiciously in England. It meant he could introduce aspects to English football that look like common sense now and be declared a visionary.

He picked up Anelka and Vieira early on because nobody else knew about them and wouldn't have gambled on them anyway. There was even scepticism when Thierry Henry arrived from Juventus.

Wenger stands alongside Thierry Henry during his unveiling at Arsenal following his move from Juventus in August 1999

These days, nearly every Premier League club has a comprehensive scouting network abroad and Wenger hasn't got a free run. Leicester City signed N'Golo Kante for £7million just over a year ago. It was a deal Wenger might have pulled off in the 1990s.

Secondly, Arsenal's leaders at the top of the club gave their new manager an unprecedented level of support rarely if ever seen for an 'unknown' in today's league.

There is a fabulous story about Wenger going to Arsenal's UEFA Cup tie away to Borussia Monchengladbach on September 25 for a watching brief shortly before he took over properly.

The new manager popped into the dressing-room at half-time, suggested some tactical alterations at the back – and the team lost 3-2 to crash out of the tournament.

Back at base, captain and legend Tony Adams pulled the caretaker-manager and soon-to-be Wenger No 2 Pat Rice to say he wasn't sure about the changes Wenger had made.

Rice's response was short and to the point: 'What the f*** has it got to do with you, Tony?'.

The message was clear from the very top to the staff Wenger was going to work with. If any of the Arsenal legends – famous Back Five or otherwise – wanted to question the new manager's methods, they'd be on their bike, not him.

Wenger celebrates winning the 2003 FA Cup final alongside Dennis Bergkamp following a 1-0 win over Southampton

It gave Wenger the confidence and powerbase to enforce a change of direction at the club. Newcastle, Liverpool or Manchester United post-Sir Alex Ferguson would love to have been able to do the same without the approval of Alan Shearer, Steven Gerrard or Wayne Rooney for example.

But Arsenal's players knew they could either buy into the new plan or go. The vast majority did; Lee Dixon, Nigel Winterburn, David Seaman, Martin Keown, Paul Merson, Ray Parlour and Adams himself – all George Graham men – prolonged their careers at Highbury, boosted by playing with world-class arrivals such as French World Cup winner Vieira, Manu Petit and Henry.

Parlour, seen very much as an energetic but limited player, thrived.

'If you told the Boss you needed to practise something a bit more, he'd stay with you at the end of training to practise. He'd be there for an hour with you on his own. Not many managers would do that.'

Arsenal won the League and FA Cup Double in Wenger's first season in 1998 and again in 2002. In 2003-04 they went through the Premier League season unbeaten. Two years later they reached the Champions League final, beaten late on by Barcelona.

And this was a Premier League arguably far stronger than it is today. United's Class of 92 were Treble winners, Rafa Benitez and Jose Mourinho made their entrances at Liverpool and Chelsea in 2004.

Arsenal were a selling club by then to fill their new stadium. Vieira, Henry, Marc Overmars and others left for financial reasons, Dennis Berkgamp and the Arsenal back-five retired.

Wenger ended a nine-year trophy drought by lifting the FA Cup in 2014 following a 3-2 win over Hull at Wembley

The replacements weren't as good with the exception of Robin van Persie and Fabregas, who also ended up leaving.

Football moved on but Wenger stayed obstinate. Arsenal never appointed a Director of Football and the club seemed to miss out on deals. From signing the best for knockdown prices, Wenger resorted to signing the likes of Mikel Arteta and Per Mertesacker in deadline day panic buys.

His interest in English players subsided after an unhappy experience with Francis Jeffers. Theo Walcott, Alex Oxlade-Chamberlain and Calum Chambers were signed young but never developed.

Wenger's style remained that of idealist rather than a pragmatist. Former Arsenal player Paul Davis remembered from his time as a coach mannequins popping up on training pitches to get the players to thread passes through narrow spaces.

When Davis left the club, he returned a couple of years later for a training ground visit. 'I expected the mannequins to have gone because Arsenal hadn't been that successful relatively.

'But instead he'd doubled the number of mannequins on the pitch. It was almost if as he was saying, I'm still going to play that way, but even more so.'

That puritanical streak has upset some Arsenal fans who want Wenger's 20th anniversary season to be his last before the legacy is tarnished.

Wenger developed an intense rivalry with Manchester United manager Sir Alex Ferguson during the Premier League era

But the backing for the manager during home games at the end of last season shows there is still support from the 'silent majority' who take the view that 'Arsene Knows'.

Whatever happens next, if Wenger never wins another game of football in his life, his legendary status is assured. Those like Ferguson who doubted his intentions towards the English game have long since changed their minds.

Wenger has won the country's quintessential knockout competition, the FA Cup, more times than any other manager in history, at a time when plenty of English managers and proud LMA cardholders have disrespected the competition by naming weakened teams.