The
Tridentine calendar reserved 26 April as the feast day of Saint Cletus, who the church honoured jointly with
Pope Marcellinus, and 13 July for solely Saint Anacletus. In 1960,
Pope John XXIII, while keeping the 26 April feast, which mentions the saint under the name given to him in the Canon of the Mass, removed 13 July as a feast day for Saint Anacletus. The 14 February 1961 Instruction of the Congregation for Rites on the application to local calendars of
Pope John XXIII's
motu proprio Rubricarum instructum of 25 July 1960, decreed that "the feast of 'Saint Anacletus', on whatever ground and in whatever grade it is celebrated, is transferred to 26 April, under its right name, 'Saint Cletus'". Priests who celebrate Mass according to the
General Roman Calendar of 1954 keep the July 13th feastday; but the feast has been removed from the
General Roman Calendar since 1960, and as such is not kept even in the 1962 Missal. Although the day of his death is unknown, ==In literature==