Captain Vincent Kompany says he will leave Manchester City after Saturday's FA Cup final win over Watford.
The 33-year-old defender won four Premier League titles, two FA Cups and four League Cups during 11 years at Etihad Stadium in which he scored 20 goals in 360 games.
By beating Watford 6-0 at Wembley, City became the first men's side to complete the domestic treble in England.
In an open letter on Facebook, Kompany said it "doesn't feel real".
"Countless of times have I imagined this day," he said. "After all, the end has felt nearby for so many years.
"Man City has given me everything. I've tried to give back as much as I possibly could."
Belgium centre-back Kompany joined City from Hamburg as a defensive midfielder in 2008 and was named club captain three years later.