Christmastide provides a strange array of moving feasts that are only more confusing when one begins with the Anglican Prayer Book tradition and then expands to the current Western calendar. The particular feasts I have in mind are the Solemnity of the Mother of God, the Circumcision of Christ, the Feast of the Holy Name, the feast of the Holy Family, and the Baptism of Our Lord.
The 1662 English BCP was quite simple: it kept the three feasts that immediately follow Christmas (St Stephen, St. John the Evangelist, and Holy Innocents); the octave day of Christmas, Jan 1, as the Circumcision of our Lord; Epiphany on the traditional 13th day after Christmas, Jan 6; and the Purification of Mary, the Blessed Virgin (also, the Presentation or Candlemas) on Feb 2, 40 days after Christmas. There is no feast of the Holy Name (and the Circumcision collect makes no mention of the Name), no Marian feast, no Holy Family, and no feast of the baptism of Jesus. The American BCPs through 1928 edition were no different than their English counterparts in this regard.
The 1979 American revision, however, included some significant revisions to the calendar in Christmastide. The three feasts immediately after Christmas remain unchanged. However, the octave day of Christmas is no longer the Circumcision but the feast of the Holy Name, complete with a new collect. This is noteworthy, since the feast of the Holy Name was quite late in the West, being popularized by the Franciscans in the 15th century, and as such, it is less likely to be a source for a liturgical text so marked by the end of the liturgical movement (i.e. the 1979 American BCP). But, of course, the celebration is quite logical, since it is the flip side of the Circumcision, as the giving of “Jesus” as a name to the incarnate Lord is constitutive of the Jewish rite. The day on which this feast was celebrated was also quite varied: “Franciscans, Carmelites, and Augustinians kept the feast on 14 January; Dominicans on 15 January; in some localities the date was 8 January, in others 31 January, in some localities in Great Britain on 7 August. The Society of Jesus, i.e., the Jesuits, celebrates the Holy Name of Jesus on 3 January as the order’s own titular feast. The date of the second Sunday after Epiphany was chosen by the Carthusians, then by Spain. This was the date assigned to the celebration when, on 20 December 1721, it was inserted into the General Calendar of the Roman Rite by Pope Innocent XIII. In the reform of Pope Pius X, enacted by his motu proprio Abhinc duos annos of 23 October 1913, it was moved to the Sunday between 2 and 5 January inclusive, and in years when no such Sunday existed the celebration was observed on 2 January; this is still observed by Catholics following calendars of 1914 to 1962. The reform of the liturgical calendar by the motu proprio Mysterii Paschalis of 14 February 1969 removed the feast “since the imposition of the name of Jesus is already commemorated in the office of the Octave of Christmas.” However, the Mass texts of the Holy Name of Jesus were preserved, being placed with the Votive Masses. The celebration was restored to the General Roman Calendar with the 2002 Roman Missal” (thanks to Wikipedia for this helpful summary). Currently, the Holy Name is an optional memorial in the General Roman Calendar on January 3.
A second revision in the 1979 BCP further emphasized the connection between Epiphany and the Baptism of Jesus by making the first Sunday after the Epiphany the Feast of the Baptism of our Lord, with a new collect based on two in the Roman sacramentary. The Baptism has long been part and parcel of the celebration of the Epiphany (Theophany) in the East. A distinct feast did not appear in the Roman Rite until 1955 when it was inserted into the General Roman Calendar by Pius XII on January 13, the octave day of the Epiphany (thus replacing the propers for the octave day). Not long after, the feast was moved by Paul VI to its current location as the Sunday after the Epiphany (the Monday after it begins ordinary time).
The Roman practice regarding the date of January 1 is similarly complicated.
First, it seems that the earliest feast of Our Lady was celebrated in many places on the Sunday before Christmas. But in time, this developed quite widely into the feast now fixed on August 15, and celebrated as the Assumption of the Blessed Virgin in the West. It is worth noting that this feast appeared for the first time in the 1979 American BCP, with a very “assumption” collect to boot: “O God, you have taken to yourself the Blessed Virgin Mary,” it begins. In parts of the West, the octave of the nativity of our Lord was celebrated as his circumcision, according to the chronology given in Luke 2:21, which identifies both the fact that his ritual incorporation into Israel was in accordance to the Law, and that on the eighth day after his birth he was given the Name revealed separately to both Mary and to Joseph by the word of an angel. This feast of the Name appears sometime after the Council of Tours in 567 in Spain and Gaul; but by the seventh century, the Roman practice is that the Octave is a feast of the Blessed Virgin, as attested in the Gregorian Sacramentary. But by the 11th century, January 1 tended to be listed as the Circumcision of Jesus, and thus was retained in the English BCP calendar as such, all the way until the 20th century. However, the 1969 revision of the Roman calendar returned Jan 1 to the older Roman practice of commemorating the Mother of God as a solemnity on the octave day of the Nativity.
The final addition to the Christmastide calendar in the West came with the introduction of the feast of the Holy Family by Lei XIII in 1893 on the Sunday within the Octave of the Epiphany (now the Baptism of our Lord, since the octave was abolished by Paul VI). In the General Roman Calendar revised by Paul VI, the Feast was moved to the first Sunday after Christmas (or, if both Christmas and its octave are on Sundays, on the Friday between them).
Thus, the Episcopal Church followed the practice of the Latin Church in a number of its own calendrical revisions in 1979, but not all corresponding to the revisions of the General Roman Calendar by Paul VI after Vatican II:
Jan 1 is not longer the feast of the Circumcision; but neither is it the feast of the Mother of God, as in the current Roman calendar; instead, it is the Feast of the Holy Name, a barely pre-Reformation feast that is now an optional memorial in the Roman Calendar for Jan 3.
The Sunday after the Epiphany is now the Baptism of Our Lord, in unison with the General Roman Calendar revised by Paul VI.
The 1979 BCP has propers for both the first and second Sundays after Christ, but neither have any emphasis on the Holy Family, as in the current General Calendar on the Sunday within the octave of Christmas.
Furthermore, the 1979 introduces the oldest widespread feast day for the Blessed Virgin on August 15, including a collect that points to the Assumption.
Finally, outside of Christmastide, the Episcopal Church followed the current Roman Calendar in celebrating the last Sunday of Ordinary Time and the Sunday before Advent 1 as the Feast of Christ the King. Though instituted by Pius XI in 1925 for the last Sunday in October, it was moved by Paul VI in his revision of the General Calendar to its current location. Oddly, however, the 1979 BCP never uses the title of Christ the King for the Sunday at any point, even though the collect is taken directly from the current Roman Missal (it also has no proper preface for the feast, and strangely assigns it either one of the three Lord’s Day prefaces or that of Baptism).