After the annual celebration of the Paschal mystery, has nothing in higher esteem the Church that the celebration of the birth of the Lord and its first manifestations: this takes place at Christmas time.
Christmas time ranges from the first Vespers of Christmas until the Sunday after Epiphany, or the first Sunday following January 6, inclusive.
Christmas vigil mass is used on the evening of December 24, before, either after first Vespers.
On Christmas day you can celebrate three masses, in accordance with the ancient tradition of Roman, i.e. in the evening, to lighten the aurora and day.
Christmas only has the eighth ranked in this way:
a) on Sunday of infraoctava (which follows him to 25 December) the feast of the Holy family takes place.
(b) on December 26 is the feast of St. Stephen, Protomartyr (first martyr).
c) on 27 December, the feast of San Juan Apóstol and evangelist.
d) on 28 December of the Holy Innocents.
(e) the days 29, 30 and 31 are infraoctava.
(f) the first day of January – octave of Christmas – celebrate the solemnity of the Virgin María Madre de Dios, in which the Church commemorates also the imposition of the most holy name of Jesus.
The Sunday that falls between 2 and 5 January, is the II after Christmas. See BestCraftBlog for more.
The Epiphany of the Lord is celebrated on 6 January, unless assigned a Sunday that falls between day 2 and January 8.
The Sunday following on 6 January will be held on the feast of the baptism of the Lord.