BBC Sport looks at vice-chairman David Dein's shock departure from Arsenal and the possible ramifications for the club.
WHY HAS HE GONE?
Arsenal's statement explained that "irreconcilable differences between Mr Dein and the rest of the board have necessitated a parting of the ways".
Dein has left Arsenal after a 24-year association with the club
Put simply, Dein apparently supported a takeover by American billionnaire Stan Kroenke, while the rest of the board were against it - at least for now.
"Two days ago, there was a very secret board meeting at Arsenal where it was made clear to Dein that he had to go," explains BBC Sport editor Mihir Bose.
"Dein has always wanted Arsenal to float (on the stock exchange), like Manchester United did, but the rest of the board members, including chairman Peter Hill-Wood and major shareholder Danny Fiszman, don't want that.
"Fault lines have developed within the Arsenal board over the last few years and clearly the intervention of Kroenke created a flashpoint."
WHAT HAVE ARSENAL LOST?
Dein's association with the club stretches back to 1983 when he bought a 16.6% share of the club for a little under £300,000.
The 63-year-old gradually built up his shares until he had a 42% stake in 1991 - the year before the inception of the Premier League which would revolutionise the finances of England's top clubs.
Since then, he is thought to have earned more than £10m by selling off many of his shares to Fiszman - although Dein still has a 14.5% stake in the club.
1983 - Buys 16% share in Arsenal
1990 - Dein and Liverpool director Noel White approach the FA with plans by big clubs to break away from Football League
1996 - Is driving force behind Arsene Wenger's appointment
2000 - Is elected Premier League representative on the FA board
2006 - Is voted off FA board but is appointed chairman of G14 group of Europe's top clubs
But Dein's legacy lies in his appointment of Arsene Wenger in 1996.
It was by no means a popular move.
Dein, by then the vice-chairman, faced the wrath of fans at an August shareholders' meeting that year after Bruce Rioch had been sacked just five days before the start of the season, with Wenger unable to take up his new post until the end of September.
But the move proved to be a stroke of genius as Arsenal went on to become twice Double winners under Wenger.
WILL DEIN'S DEPARTURE AFFECT WENGER'S FUTURE?
When Wenger arrived in 1996, he immediately forged a close working relationship with Dein.
Wenger's policy of unearthing untapped foreign talent married perfectly with Dein's desire for Arsenal, and the English game as a whole, to broaden its horizons.
It was Dein who backed Wenger in the transfer market and Dein who fought off the advances of Real Madrid when they came knocking two years ago.
Dein always looked after football matters at the club. He did all the transfer deals and all the talking with Wenger
BBC Sport editor Mihir Bose
And it was Dein, then a member of the Football Association's executive committee, who was last year accused of shielding Wenger from the selection process when England were looking for a manager to succeed Sven-Goran Eriksson.
Dein was also a key figure in Thierry Henry's decision to commit his future to Arsenal last year, with Dein's son Darren, Henry's best man at his wedding, leading the negotiations.
Chairman Hill-Wood has reassured Gunners fans that Wenger's relationship with the rest of the board is "good", but with only a year remaining on his contract and his principal ally at the club gone, questions are bound to be raised about the Frenchman's future.
"Dein always looked after football matters at the club. He did all the transfer deals and all the talking with Wenger," says Bose.
"Maybe the board are reassured that Wenger has a long association with the club and will not go.
"Maybe they feel that this was a much more important matter: to keep the people who have historically been in charge of Arsenal in control and not have Americans come in."
HOW LIKELY IS A TAKEOVER?
After announcing Dein's departure, Hill-Wood revealed that the remaining board members, who between them own 45% of the club, had agreed not to dispose of their shares for at least one year.
Hill-Wood has also been quoted as saying he would be "horrified if the club were to go across the Atlantic".
Danny Fiszman 24%
Lady Bracewell-Smith 15.8%
Richard Carr 4.35%
Peter Hill-Wood 0.8%
David Dein 14.5%
Stan Kroenke 11.26%
Small investors 18.03%
However, Dein's departure from the board raises the possibility that he could sell his 14.5% share in the club to Kroenke and join forces with the American, nicknamed 'Silent Stan'.
However, even if Kroenke were to buy Dein's shares, football business expert Professor Tom Cannon reckons a hostile takeover would be "very difficult" to achieve.
"They trade on the Ofex (Plus Markets) which is the off-the-stock-market exchange," Cannon told BBC Five Live.
"It's very hard to see how a takeover could succeed if you have those shareholders on the board with 45% of shares saying no.
"One can be pretty confident that from the smaller shareholders they can pick up the remaining 5% of shares to pretty well control 50% of the shares and therefore it's almost inevitable they will be able to block a full-blown takeover."
WHAT DO THE FANS MAKE OF IT?
Selected comments from BBC Sport's 606 website:
"I have a feeling Dein will be back with Kroenke. I would not be at all surprised if he were to put his shares together with Kroenke and try to force a takeover. At least I hope so. I have a lot of respect for the people that have owned the club for years and the fact they'd like to 'keep it in the family' - but Dein has been massively influential."
"It seems David Dein was an advocate of the American takeover. It's a shame the club are heading in that direction rather than sticking to their traditions. It's a trend for American entreupeneurs to buy football clubs and the profit margins are increasing, hence their one and only reason to do so. Seems David Dein felt he could cash in on a buy out and the others objected. Interesting times lie ahead.
"Sorry guys, but the days of the old school tie boardroom died at Arsenal years ago. So why not welcome Stan Kroenke and his wealth of cash and business sense? If my suspicions are correct I think David Dein may be back in charge pretty soon."
"David Dein is the reason where Arsenal stand as a club in the world today. He had vision, he brought in Wenger and believed in him when no-body else did. It's a tragic thing to Arsenal and I hope the club recovers as soon as possible. I hope there will be no takeover."