Former England captain Chris Robshaw will leave Harlequins at the end of the season.
Robshaw made his Quins debut in 2005 and has gone on to make 289 appearances for the club and earn 66 England caps.
The 33-year-old flanker was named skipper of the club in 2010, leading them to the European Challenge Cup title in 2011 and Premiership glory the following year.
In a letter posted on the Quins' website, Robshaw said: "As a boy, wearing my oversized Harlequins shirt, I could never have imagined I would be fortunate enough to play for the team I admired the most. Which is why it has been a particularly difficult decision for me to leave the club after 16 extraordinary years.
"I will be hanging up my Harlequins shirt at the end of the season. And though there is so much I will miss about playing for this team, I will always be eternally grateful and proud for having had the chance to stand alongside such extraordinary players. All the while, being supported by the best fans in the world.
"I look forward to the next chapter in my life and will keep you posted. But wherever I end up next, I will do my utmost to make you proud."