In the novel 'The Count of Monte Cristo' how long was Edmond Dantes in prison for?

21 years. Seven years in solitary confinement and just when he begins to give up hope, he meets the abbot, from whom Dantes learns a lot for the next 14 years. he escapes from the prison after the Abbot's death, by moving the abbot's dead body into his cell and by hiding himself in the sack meant to throw away the dead body.

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