Purgatory, a place in which, according to the doctrine of the Roman Catholic Church, expiation is made for sins which remained unpunished during the sufferer's lifetime. The belief in such a place rests on the view that, although the penalty of eternal torment has been remitted through the death of Christ, Divine justice requires that every sinful act should be followed by temporal punishment, either in this world or in the next. Gregory the Great was the first who distinctly formulated the doctrine afterwards accepted by the Councils of Florence (1439) and Trent (1545-63). The canons of these Councils not only assert the existence of a Purgatory, but declare that the sacrifice of the Mass and the prayers and alms of believers are efficacious in relieving the sufferings of those who are there detained. They make no statement, however, as to the locality of Purgatory or the character and duration of the punishment.