Aitor Karanka threatened to quit more than once before Nottingham Forest called time on his tenure, Sportsmail can reveal.
The Spaniard left the club on Friday after he 'asked to be released from his contract' following a series of clashes behind the scenes.
Karanka's position was precarious ever since the Boxing Day draw at Norwich, although owner Evangelos Marinakis actually requested his manager stay during discussions on Thursday - but a parting of the ways became inevitable.
It is understood Slavisa Jokanovic is a contender for the position and has been sounded out due to his record for getting Watford and Fulham into the Premier League. Carlos Carvalhal and Martin O'Neill are also candidates. In the meantime Simon Ireland will take charge, assisted by Michael Dawson.
As revealed by Sportsmail in October, Marinakis demanded results improve during an address at the training ground, and there is still frustration at the side's position, four points off the play-offs, after a £25million summer spend.
It is understood Karanka did not respond well to the challenge and instead made demands for more money in the market, creating major friction with the club's hierarchy.
The 45-year-old is alleged to have exhibited mood swings and pushed back for power. His latest vow to leave meant it was uncertain whether he would show up for training on Thursday.
Marinakis originally planned his visit to Nottingham to discuss transfer plans but was told by Karanka he wanted out.
Karanka was known to be annoyed at the hiring of director of football Kyriakos Dourekas at the start of December, and fought against the potential appointment of Jose Anigo, a former Marseille manager, as sporting director.
Karanka's reaction was similar in his previous role at Middlesbrough when Victor Orta joined to lead recruitment.
Karanka also developed a strained relationship with chief executive Ioannis Vrentzos as well as several players.
Amid the disputes, Marinakis considered a dismissal after Forest let slip a 3-0 lead at Carrow Road a fortnight ago but tried to make things work. He then watched a defeat at Millwall and a victory over Leeds before a loss to Chelsea in the FA Cup.
Both parties wrestled over the exact terms of his departure before an announcement was made on Friday morning.