In the course of the calendar year, Catholics celebrate certain important events in the life of Christ and his Church on days which do not fall on Sunday.  These special days, officially called Solemnities, have the same status as Sundays and are refered to as days of obligation because the Church expects its members to participate in the celebration of Mass on these days.  In the universal church there are ten such days, although Canon Law allows the local conference of bishops to add to, suppress, or transfer some of them to Sundays.

   In the United States there are six holy days of obligation:

Solemnity of Mary, Mother of God
January 1

   On this feast the Church celebrates its belief that in Mary’s womb the Second Person of the Trinity united himself completely with our humanity; the feast honors not only Mary but Jesus, true God and true man. The title “Mother of God” is the Western church’s equivalent of the ancient Eastern title Theotokos, which means “God-bearer.” The Council of Ephesus sanctioned the title Theotokos for Mary as a way of protecting the divinity of Christ in 431. The Feast of the Divine Maternity was approved for Portugal in 1751 and extended to the whole church in 1931, the 1500th anniversary of the proclamation of the dogma at Ephesus. It was transferred to January 1 by the calendar reform in 1970. 
The Solemnity of Mary, Mother of God is not a holy day of obligation when it occurs on a Saturday or Monday.
> Learn more about the Solemnity of Mary, Mother of God here and here.

Solemnity of the Ascension
40 Days After Easter

   At the end of His earthly life Jesus ascended into heaven. To avoid getting confused about the geography of the Ascension, it is important to remember that heaven is a state of being, not a physical place. What we celebrate today is the Lord’s (re)union with the Trinity--the completion of the resurrection. The Lord’s Ascension is the pledge of our own; while mindful of the Lord’s continued sacramental presence among us here and now, we look forward to the state of eternal happiness which we will eventually share with him.  This feast is traditionally observed 40 days after Easter Sunday, which falls on a Thursday. However, most Catholic dioceses in the United States have transferred the celebration of this feast to the following Sunday.
> Learn more about the Solemnity of the Ascension here and here.

Assumption of the Blessed Virgin Mary
August 15

   The solemnity of the Assumption celebrates the Catholic belief that Mary, the mother of Jesus, was assumed body and soul into heaven at the end of her earthly life. This event was celebrated under various names (the “Commemoration,” “Dormition,” “Passing” or “Assumption”) from at least the fifth or sixth century. The formal doctrine of the Assumption was proclaimed by Pope Pius XII in 1950. Since Mary is closely associated with all the mysteries of Jesus’ life, the Church is confident that she shares in his glorification as will eventually all of the faithful departed.
In most dioceses of the United States, the celebration of the Assumption of the Blessed Virgin has been transfered to the Sunday following August 15.  It is not a holy day of obligation when it occurs on a Saturday or Monday. 
> Learn more about the Assumption of Mary here and here.

Solemnity of All Saints
November 1

   The earliest certain observance of a feast in honor of the Saints is an early fourth-century commemoration of  “all the martyrs.” Pope Boniface IV dedicated May 13 as a feast in honor of Mary and all the martyrs in the seventh century and Pope Gregory III changed the date to Nov. 1 when he created an oratory for the relics of martyrs and saints at St. Peter's in the mid-eighth century.  Originally, this feast honored the official and unofficial Saints in heaven but is often expanded to include all of the baptized who are at least potential Saints or Saints-in-waiting and who share in what the Second Vatican Council called “the universal call to holiness.” 
The Solemnity of All Saints is not a holy day of obligation when it occurs on a Saturday or Monday.
> Learn more about the Solemnity of All Saints here and here.

Solemnity of the Immaculate Conception
December 8

   The doctrine of the Virgin Mary's Immaculate Conception developed gradually over time and in large part grew out of the piety of common faithful rather than the theology of the Church’s teachers. A feast called the Conception of Mary arose in the Eastern Church in the seventh century and spread to the West. In the 11th century it received its present name and by the 18th century was recognized as a feast of the universal Church. In 1854 Pope Pius IX defined the solemn dogma of the Immaculate Conception, according to which “the most Blessed Virgin Mary was, from the first moment of her conception… preserved immune from all stain of original sin.”
> Learn more about the Solemnity of the Immaculate Conception here and here.

Solemnity of the Nativity of the Lord
December 25

   No one knows exactly when or why the Church chose December 25 as the date for Christmas, but there is evidence that December 25 was the date being celebrated in Rome as early as the year 336. One theory is that it was a response to the Roman Emperor Aurelian’s decision in 274 to make December 25 the date for honoring the Syrian sun-god Emesa. A second theory is based on efforts of the early Christian community to calculate the birth of Jesus based on the solar calendar, using equinoxes and solstices as cosmic dates around which important human events were timed. In any case, the new feast spread rapidly throughout the western Church and was almost universal by the end of the fourth century.  The Eastern church continues to celebrate the birth of the Lord on the Feast of the Epiphany.
> Learn more about the Solemnity of the Nativity of the Lord here and here.
 

Last Update: 04.06.24