The 68-year-old arrived at the London club in 1996 a relative unknown but leaves widely hailed as the greatest manager in Arsenal's history after three Premier League titles and a record-breaking seven FA Cup triumphs.

Wenger, who completed the Premier League and FA Cup double in his first full season in England, was hailed as an innovator in his early years and his spiky clashes with former Manchester United boss Alex Ferguson became the stuff of legend.

Yet despite cup success in recent years, fans have become increasingly frustrated by the club's inability to challenge the likes of Manchester City and Chelsea for the Premier League title and a failure to reach the sharp end of the Champions League.

"After careful consideration and following discussions with the club, I feel it is the right time for me to step down at the end of the season," Wenger said in a statement posted on the club's website.

"I am grateful for having had the privilege to serve the club for so many memorable years."

Wenger arrived at the Emirates with Ferguson's United at the peak of their powers but immediately threw down the gauntlet, winning the Premier League and FA Cup double in 1998, before repeating the feat four years later.

But perhaps the most remarkable achievement of his long reign was going through a full league season unbeaten in 2003-04, with his "Invincibles" playing a captivating brand of fluid football.

Champions League              
                  
But after an incredible 19 successive years in the Champions League, Arsenal, in sixth place in the Premier League, could miss out for the second consecutive year after a disappointing league campaign.

Their only realistic chance of qualifying for next season is by winning the second-tier Europa League -- the Gunners face Spanish giants Atletico Madrid in the semi-finals -- and Wenger has urged the fans to get behind the club.

"I urge our fans to stand behind the team to finish on a high," said Wenger. "To all the Arsenal lovers take care of the values of the club. My love and support for ever."

Arsenal's majority shareholder Stan Kroenke paid tribute to a man of "unparalleled class".

"Everyone who loves Arsenal and everyone who loves football owes him a debt of gratitude," said Kroenke, who took a controlling stake in the club in 2011.

"One of the main reasons we got involved with Arsenal was because of what Arsene has brought to the club on and off the pitch. His longevity and consistency over such a sustained period at the highest level of the game will never be matched."

Arsenal added that a successor to Wenger will be found "as soon as possible".
                  
Frustration         

Wenger took charge with Arsenal in the doldrums in October 1996, but quickly set about a revolution in English football by overhauling players' diets and bringing an end to the drinking culture that had dogged the club.

Results soon arrived on the pitch as Wenger's men beat an all-conquering Manchester United side to the title in 1997-98 and won the league again four years later.

Despite their constant presence in the Champions League Wenger was never able to end Arsenal's quest to win the competition for a first time. They closest they came was in 2006 when a young side was edged out 2-1 in the final by Barcelona.

That season was also Arsenal's final campaign at Highbury but the promise that moving to the 60,000-capacity Emirates Stadium would allow the club to compete financially with the biggest spenders in England and the continent failed to materialise.

Instead, Wenger was much criticised for his unwillingness to spend the money needed to keep up as booming TV revenues saw Premier League rivals splash the cash in an arms race.

Arsenal even sold a host of star players such as Thierry Henry, Cesc Fabregas and Robin van Persie.

And the fans' frustration continued to grow as, even after loosening the purse strings to buy Mesut Ozil in 2013 and Alexis Sanchez a year later, Arsenal still failed to compete for the title or the Champions League.