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."
|Brotherly g-love! Tommy Fury follows Tyson into the pros|
|Ozil´s international retirement can help Arsenal - Emery|
|If you sack Lopetegui, you have to sack us all – Isco|
|Lopetegui defiant amid Real Madrid sack reports|
|Sri Lanka spinner Herath to retire after Galle Test|
|Ronaldo returns for Old Trafford welcome amid disquieting noise|
|Garcia claims third Andalucia Valderrama Masters title|
|Ex-England international Waldrom retires|
|´Massive personality´ Hart can lift Burnley, says Kompany|
|Liverpool felt wrath of ´emotional´ Klopp, says Shaqiri|
|Reid: Jenkins capitalised on Kaepernick movement|
|Manchester United v Juventus: Ronaldo out to end dismal scoring record against Mourinho|
|Injured Ribery to miss Bayern´s clash with AEK|
|Wilshere would have stayed at Arsenal under Wenger|
|Mahomes stars again as Chiefs crush Bengals|
|Bolt must accept ´much less´ to join Mariners, says A-League chief|
|Klopp compares Liverpool to dog without favourite toy|
|Young leads Hawks to first win, Thunder fall in Westbrook´s return|
|Spalletti hits out at physical Milan – I had three players asking to be replaced|
|Cowboys, Ravens lose after missed kicks in final seconds|
|Hernangomez secures Nuggets´ win over Warriors with last-second block|
|Hasler returns to Manly on three-year deal|
|Sarri: Chelsea fans must respect Mourinho|
|Ronaldo learnt from Scholes – Pjanic praises Juventus star|
|CA dismisses spot-fixing claims|
|WATCH: Will Ferrell leads chants with LAFC fans|
|MLS Review: Galaxy on track for play-offs as Timbers, DC clinch spots|
|Elliott secures win at Hollywood Casino 400|
|Thunder´s Westbrook makes season debut against Kings|
|Saints beat Ravens after Tucker misses extra point|
|Rondo, Paul and Ingram banned after Lakers-Rockets fight|
|Saints QB Brees reaches another historic milestone|
|Biglia: VAR should have checked Nainggolan tackle|
|Gattuso not blaming Donnarumma for derby defeat|
|Seventh in Mexico will secure Hamilton´s fifth world title|
|Rooney fires DC United into MLS play-offs|
|Alonso slams ´amateur´ F1 rivals after latest crash|
|Spalletti fears lengthy Nainggolan absence|
|To the Max! Verstappen destroyed shoe fending off Hamilton|
|Icardi delight after Donnarumma error gives him another derby winner for Inter|
|Guardiola: Versatility the key for Stones|
|Vettel frustrated as mistakes continue to hamper title challenge|
|ECB refutes spot-fixing claims against England players|
|I thought we would do better - Hamilton queries Mercedes strategy|
|Inter 1 AC Milan 0: Icardi settles derby with dramatic late winner|
|Hamilton denied title party as Raikkonen wins in Austin|
|Patriots RB Michel out against Bears with gruesome knee injury|
|Kohli hails Rohit partnership after comprehensive India victory|
|Silva downplays his role after Everton super subs seal victory|
|Injured Bairstow out of final white-ball matches in Sri Lanka|
|Pliskova feeling confident after impressive start in Singapore|
|Big-hitting Imrul rescues Bangladesh in opening ODI|
|Leinster suffer late defeat at Toulouse, Newcastle snatch dramatic victory|
|Chargers pip Titans to dramatic London win|
|Everton 2 Crystal Palace 0: Substitutes Calvert-Lewin and Tosun clip Eagles´ wings|
|Thunderstorms push Andalucia Valderrama Masters into reserve day|
|Edmund masters Monfils to claim maiden singles title|
|Kohli and Rohit fire India to comprehensive ODI win|
|Manchester United didn´t play - David Luiz blasts Mourinho tactics|
|Svitolina out to silence ´haters´ in Singapore|
|Emre Can facing surgery on thyroid problem|
|Tsitsipas claims maiden ATP crown in Stockholm|
|Mariners boss Mulvey knows nothing of Bolt contract offer|
|WATCH: Vinicius Junior scores free-kick - then sees red!|
|Gronkowski ruled out of Bears clash|
|Khachanov enjoys home comforts with comprehensive Kremlin Cup win|
|Isner wants Wimbledon tie-break rule named after him|
|Hummels lauds ´outstanding´ Lewandowski|
|Liverpool´s defensive improvement no accident – Gomez|
|Pliskova overpowers defending champion Wozniacki in Singapore|