Roman Catholic liturgical calendar

The General Roman Calendar is the liturgical calendar that indicates the dates of celebrations of saints and mysteries of the Lord (Jesus Christ) in the Roman Rite, wherever this liturgical rite is in use. These celebrations are a fixed annual date; or occur on a particular day of the week (examples are the Baptism of the Lord in January and the Feast of Christ the King in November); or relate to the date of Easter (examples are the celebrations of the Sacred Heart of Jesus and the Immaculate Heart of Mary). National and diocesan liturgical calendars, including that of the diocese of Rome itself, as well as the calendars of religious institutes and even of continents, add other saints and mysteries or transfer the celebration of a particular saint or mystery from the date assigned in the General Calendar to another date.

These liturgical calendars also indicate the degree or rank of each celebration: Memorial (which can be merely optional), Feast or Solemnity. Among other differences, the Gloria is said or sung at the Mass of a Feast, but not at that of a Memorial, and the Creed is added on Solemnities.

The last general revision of the General Roman Calendar was in 1969 and was authorized by the motu proprio Mysterii Paschalis of Pope Paul VI. The motu proprio and the decree of promulgation were included in the book Calendarium Romanum, published in the same year by Libreria Editrice Vaticana. This contained also the official document Universal Norms on the Liturgical Year and the Calendar, and the list of celebrations of the General Roman Calendar. Both these documents are also printed (in their present revised form) in the Roman Missal, after the General Instruction of the Roman Missal. The 1969 book also provided a detailed unofficial commentary on that year's revision of the calendar.

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