Arsenal chief executive Ivan Gazidis has resigned to join AC Milan, the Premier League club have announced.
The 54-year-old will step down at the end of October, following a decade at Emirates Stadium, and take up the same role at Milan on December 1.
Raul Sanllehi and Vinai Venkatesham will head up football operations at Arsenal, taking up the head of football and managing director roles respectively.
Sanllehi, a former director of football at Barcelona, joined the Gunners as head of football relations in February, while Venkatesham is currently the club's chief commercial officer.
Gazidis headed up the interview process that lead to Unai Emery's appointment as head coach, succeeding long-serving manager Arsene Wenger.
His overhaul of Arsenal's structure, including the appointments of Sanllehi and head of recruitment Sven Mislintat, arguably helped to herald the end of the Wenger era as a degree of power was wrestled away from the veteran Frenchman, and Gazidis has described his pending departure as "the hardest decision of my life".
Raul Sanllehi and Vinai Venkatesham appointed head of football and managing director respectively, as Ivan Gazidis leaves for A.C. Milan— Arsenal FC (@Arsenal) September 18, 2018
"For the last 10 years I have been privileged to dedicate myself to this great club. Arsenal is entering a new chapter and I have done everything I can to ensure that it is strongly placed to take on that challenge," he said in a statement on Arsenal's official.
"This includes world-class facilities and outstanding leaders in every sector who carry the values of the club, including, of course, Unai Emery, Raul Sanllehi and Vinai Venkatesham, in whom I have enormous faith.
"Although it is very hard to do - the hardest decision of my life - I believe that, after 10 years, it is the right time for me to step aside to allow new leadership, energy and ideas to take the club forward into this exciting new era.
"While this is the most difficult and challenging course for me, I am excited to see what the future holds for this great club.
"After so many years at Major League Soccer and Arsenal, I am now looking forward to joining one of the world’s other great clubs, AC Milan, and working to restore it to its rightful place in football. Until then, I will continue to devote absolutely all my energy until my last day to ensure an orderly transition for the benefit of Arsenal Football Club."
Gazidis is the latest addition to the Milan board under new owners Elliott Management, with club great Paolo Maldini working as sporting strategy and development director alongside former team-mate Leonardo, who is sporting director.
"I am very excited to take on this new challenge and will do everything I can to secure AC Milan’s return to the top," Gazidis said in a statement released by Milan.
"I have a head start in this project thanks to the talented players, hard-working staff, and the sporting leadership of Leonardo De Araujo, Paolo Maldini and [head coach] Gennaro Gattuso.
"I am grateful for the trust placed in me by chairman Paolo Scaroni, the AC Milan board, and the club's owners."
|Casillas reaches 100 Champions League wins|
|Expansion franchise Cincinnati sign Garza, send Kamara to Rapids|
|Manchester City sign United States goalkeeper Steffen for reported £7m|
|Schalke 1 Lokomotiv Moscow 0: Russians miss chance for Europa League reprieve|
|Galatasaray 2 Porto 3: Terim´s men into Europa League after penalty drama|
|Jackman leaves Dragons role|
|Tottenham boosted as Barcelona bench Messi|
|Mane and Henderson in Liverpool XI to face Napoli|
|Mourinho shoots down question over how to get the best from Pogba|
|Ronaldo to start as Allegri aims to avoid Champions League big guns|
|Odriozola: I´m in love with Benzema, he´s the best number nine in the world|
|Vikings fire OC DeFilippo after loss to Seahawks|
|Marcelino suggests Valencia open to Batshuayi departure|
|Bottas to make rally debut in title-winning M-Sport Ford Fiesta|
|Kovac dismisses Pavard speculation|
|Yaya Toure leaves Olympiacos after just five appearances|
|Riise challenges Liverpool to banish Champions League disappointment against Napoli|
|We rallied around it - Durant on Green confrontation aftermath|
|Valencia ´p****d off´ with Fellaini´s controversial Young Boys winner - Soler|
|More must be done to combat racism at Premier League grounds – Chalobah|
|Napoli will not sack ´big signing´ Ancelotti if they miss Champions League qualification, says De La|
|Guardiola not interested in ´exceptional´ Saul|
|Shai gives Windies hope with thrilling ODI run chase|
|Ten Hag unsure whether to risk Ajax stars against Bayern|
|Erasmus to work with Bulls as Springboks assist Super Rugby sides|
|Paul Gascoigne pleads not guilty to sexual assault|
|Joshua is ´begging´ for unification fight, claims Wilder|
|Silva, Fernandinho add to Guardiola´s injury woes|
|Hosszu storms to 14th gold, Seto smashes Le Clos´ world record|
|Raheem is an incredible human being - Guardiola rallies behind City star Sterling|
|Sexton pens IRFU extension until 2021|
|Ajax boss Ten Hag can do big things, says Bayern chief Rummenigge|
|He´s good at basketball – Kerr running out of superlatives for Curry|
|Green thrilled to make Warriors return in victory over Timberwolves|
|Madrid squad great and humble - Solari responds to Ronaldo|
|Langer unsure what to expect from Perth wicket|
|Fournette subjected to alleged racial abuse in Titans loss - Marrone|
|Better and better - Mbappe hails Neymar link|
|It´s the end of one of the best movies you could ever see - James pays tribute to retiring Wade|
|NASA invites Curry to see moon rocks|
|No plan B for LaLiga Miami game after Barcelona withdrawal|
|Messi´s English haul, Neymar eyes hat-trick record - Champions League in Opta numbers|
|LeBron trumps Wade in last dance, Curry scores 38 points|
|Seahawks secure dominant win over Vikings|
|Iniesta visits Messi and former club Barcelona|
|Drake makes plea for ball thrown into stands after Miami miracle|
|´Toughest pretty boy I´ve ever met´ - Langer dismisses Paine concerns|
|Van Dijk says Liverpool can challenge for double ahead of Napoli decider|
|Hazard: I´ve always loved Real Madrid|
|Yankees interested in Machado, not Harper - Cashman|
|Warriors´ Curry believes moon landing was faked|
|76ers star Butler suffers strained groin|
|Brady: Patriots still have a lot of football to play|
|´No one died´ - Belichick´s message to Patriots after stunning loss|
|Silva lauds Digne after stunning free-kick|
|Aduriz joins Messi, Ramos in LaLiga history books|
|We have a plan - Ravens coach Harbaugh prepared for Flacco return|
|´It´s difficult to accept´ - Gracia calls for introduction of VAR|
|LaLiga press on with overseas match plan despite Barcelona withdrawal|
|PSG open Coupe de France defence at fifth-tier Pontivy|
|Hazard backs Sterling as Neville reveals England star´s Euro 2016 concerns|
|Everton 2 Watford 2: Digne salvages draw with 96th-minute free-kick|
|Barcelona could ´steal´ Kane, says Pochettino|
|Oakland Raiders fire general manager McKenzie|
|Struggling Villarreal appoint Garcia Plaza as Calleja successor|
|Warriors assign Cousins to G League team|
|Barcelona pull out of plan to play LaLiga game in Miami|
|Pochettino to keep an eye on Inter when Spurs face Barcelona|
|Pochettino confirms Walker-Peters set to start against Barcelona|
|Denver Nuggets add free agent Young|