In 1955, Pope Pius XII made several changes to the General Roman Calendar of 1954; those changes remained in force until 1960, when Pope John XXIII decreed a new revision of the General Roman Calendar (see General Roman Calendar of 1960). The changes made by Pope Pius XII thus remained unaltered for only five years.
Pius XII made those changes by the decree "Cum nostra hac aetate" of 23 March 1955.[1]
- ^ Acta Apostolicae Sedis 47(1955), pages 218-224