Tradition celebrates Marymas as a liturgical feast in the General Roman Calendar and in most Anglican liturgical calendars on 8 September, nine months after the solemnity of her Immaculate Conception, celebrated on 8 December. The feast is also included in the Tridentine Calendar for 8 September. This date is also used in the Western Rite Orthodox Church. Previous to the reforms by Pope Pius XII, the General Roman Calendar of 1954 kept the Nativity of the Blessed Virgin Mary as an Octave since the Octave was established by Pope Innocent IV in 1243.