Chelsea confirmed the relationship between Jose Mourinho and the club had "broken down" after the manager left Stamford Bridge for the first time.
Director of football Avram Grant and assistant manager Steve Clarke were put in charge of first-team affairs on this day in 2007 after Portuguese boss Mourinho departed by mutual consent.
Mourinho had led the club to two Premier League titles, the FA Cup and two League Cups after joining from Porto – Champions League winners under his management – in June 2004.
But after a poor start to the 2007-08 campaign his relationship with the club had clearly soured beyond the point of being salvaged, and the Blues hierarchy felt it had begun to affect performances.
A club statement read: "Early this morning we announced that Chelsea and Jose Mourinho had agreed to part company by mutual consent.
"The key phrase here is that there was mutual agreement. Jose did not resign and he was not sacked.
"What is clear, though, is we had all reached a point where the relationship between the club and Jose had broken down.
"This was despite genuine attempts over several months by all parties to resolve certain differences.
"The reason the decision has been taken is that we believed the breakdown started to impact on the performance of the team and recent results supported this view.
"We did not want this to continue or affect the club further."
Mourinho returned to Chelsea in June 2013, adding another Premier League crown and League Cup to the trophy cabinet in 2015. In December of that year, however, he departed west London again after losing nine of 16 league matches.
He moved to Manchester United before taking in an 18-month spell at Tottenham, which ended in April ahead of a summer switch to Roma, who won their three opening matches of the 2021-22 Serie A season under the 58-year-old.