John Terry will pass into Chelsea folklore as their greatest captain during the most successful period in their history and his announcement on Sunday that he will leave at the end of the season marks the end of an era.
Along with keeper Petr Cech, who quit last year, Frank Lampard, who departed in 2014, and Didier Drogba, who left in 2012, Terry was key to Chelsea's success in the Premier League, FA Cup, League Cup, Europa League and the Champions League.
In many ways he was even more important than the other three because he was the skipper and the heartbeat of the side no matter who was in the managerial hotseat at the club.
Despite off-field controversies, including a charge of racist abuse for which he was cleared in court, and an alleged affair with a former team-mate's ex-girlfriend, in almost 18 years Terry hardly ever let Chelsea down on the pitch.
Including caretaker and interim managers, 13 different coaches have been in charge of Chelsea since Terry made his debut as a 17-year-old in 1998.
None of them, apart from Jose Mourinho who managed Terry twice, has had more impact on Chelsea's transformation from a run-of-the-mill Premier League team to European champions under billionaire Russian owner Roman Abramovich.
In almost 700 appearances for the Stamford Bridge club, Terry was the one who represented an old school, never-say-die, thunderous approach that helped bring Chelsea more success than at any time since the club was formed in 1905.
Never the quickest player, he has supreme positional sense, a clever tactical brain, and a fearless drive in the opposition goalmouth that has brought him more headed goals than any other defender in the Premier League era.
Earlier this season, after the champions' stuttering start to the campaign, former Premier League manager Harry Redknapp said: "I still think John will be a massive player this year.
"He is close to irreplaceable and, if Chelsea are going to win the league again, I think they will need him at his best. I simply cannot see them winning it with any combination of Gary Cahill, John Stones or Kurt Zouma at centre-back."
Stones has remained at Everton and Redknapp's words have rung true because Terry, now 35, has not been at his best.
Ray Wilkins, who skippered Chelsea some 40 years ago and was one of the men to take charge of the team on a caretaker basis, in February 2009, summed up what many Chelsea fans are thinking.
"He will be a tremendous loss to Chelsea and I think there was another year left in him," Wilkins told Sky Sports.
"Not everything has gone right in his career, as we all know, but his performances on the field have been absolutely outstanding."
Former England captain Terry's season could yet finish on a high. Chelsea have improved dramatically since interim coach Guus Hiddink replaced Mourinho in December and they are through to the last 16 of the Champions League and FA Cup.
Terry's final matches for Chelsea could thus bring more honours and while that appears unlikely given their inconsistent form this season, his legacy at the club is forever assured.