Dick Advocaat has chosen not to remain as Sunderland head coach, the Premier League club have announced.
Advocaat, 67, kept the club in the top flight this season after taking over from Gus Poyet in March, but said that he no longer wishes to continue a career in club management.
Sunderland AFC chairman Ellis Short said in a statement on the club website: "Although I am extremely disappointed, I understand and absolutely respect his decision. In his brief time here he made a real impact and lifted the club with his experience and enthusiasm. We will always be grateful to him for what he achieved."
Speaking about his decision, Dick Advocaat said: "At certain moments in your life you have to make a decision and I am almost 68 years old now. A number of clubs contacted me but the decision was always Sunderland or nobody.
"I would like to thank the chairman, Lee, the staff and of course the fans. We gave everything in our time there and achieved what we set out to. Sunderland has been one of the highlights of my career."
Sunderland AFC sporting director Lee Congerton added: "I know it was a tough decision for Dick to make but he felt that he couldn't commit to the intense rigours of club management on a longer-term basis and we respect his honesty.
"In his short time here he was fantastic to work with. He had and will continue to have the utmost respect of everyone here at Sunderland.
"I would like to sincerely thank him, along with his assistant Bert van Lingen and coach Zeljko Petrovic for the hard work and dedication they showed in the last two months and they leave with the very best wishes of everyone at the club for their achievements."