The liturgical calendar includes Sunday celebrations and holy days of obligation, which commemorate special events or persons of high reverence. The days of chief importance in this group are called solemnities. They begin with the Vespers, an evening rite of prayer, on the night before the holiday. Some of these solemnities may be part of a larger cycle, such as the Epiphany.

The solemnities for the full liturgical year include the following:

• January 1: Mary, Mother of God

• January 6: Epiphany

• March 25: Annunciation

• May or June (Sunday after Pentecost): Holy Trinity

• Sunday after Holy Trinity Sunday: Corpus Christi

• Thursday forty days after Easter (or the Sunday after it): Ascension

• Friday following second Sunday after Pentecost: Sacred Heart

• June 24: Birth of John the Baptist

• June 30: First Martyrs of the Church of Rome

• August 15: Assumption

• November 1: All Saints

• Last Sunday in ordinary time: Christ the King

• December 8: Immaculate Conception

Feast days are saints' days or days celebrating the Virgin Mary; generally, they are days of lesser significance that originally sprang from the people, not the Church itself. They are commemorated within the natural day. (We should note that some of the Marian devotions have been elevated in importance.) Memorials are less significant, and they are not obligatory. For instance, Mark the Evangelist has a feast day on April 25, while Catherine of Siena is honored with a mere memorial day on April 29.

Marian Devotions

Veneration of Mary, the Mother of God, holds a special place in the Catholic Church. Known as “hyperdulia” because of the difference in degree from other forms of veneration, it is higher than veneration of saints but lower than veneration accorded to God. Several feast days are celebrated in Mary's honor:

• January 1: Solemnity of Mary, Mother of God

• May 31: The Visitation of the Blessed Virgin Mary

• July 1: Immaculate Heart of Mary

• August 15: The Feast of the Assumption

• August 22: Queenship of the Blessed Virgin Mary

• September 8: Birth of the Blessed Virgin Mary

• November 21: Presentation of the Blessed Virgin Mary

• December 8: The Solemnity of the Immaculate Conception