the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph

Matthew 1:18 ¶ Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost. ¹⁹ Then Joseph her husband, being a just man, and not willing to make her a publick example, was minded to put her away privily. ²⁰ But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost. ²¹ And she shall bring forth a son, and thou shalt call his name Jesus: for he shall save his people from their sins.

The Feast of the Annunciation is one of the twelve Great Feasts of the church year. As the action initiating the Incarnation of Christ, Annunciation has such an important place in Eastern theology that the Festal Divine Liturgy of St. John Chrysostom is always celebrated on March 25, regardless of what day it falls on—even if it falls on Pascha (Easter Sunday) itself, a coincidence which is called Kyriopascha. The only time the Divine Liturgy may be celebrated on Great and Holy Friday is if it falls on March 25. Due to this, the rubrics regarding the celebration of the feast are the most complicated of all in Eastern liturgics. The Annunciation is called Euangelismos (Evangelism) in Greek, literally meaning "spreading the Good News".

St. Ephraim the Syrian taught that the date of the conception of Jesus Christ fell on 10 Nisan on the Hebrew Calendar, the day in which the passover lamb was selected according to Exodus 12. Some years 10 Nisan falls on March 25, which is the traditional date for the Feast of the Annunciation and is an official holiday in Lebanon.

The engraving by Federico Cantu: the Madonna and Child.

The engraving by Federico Cantu: the Madonna and Child. The Madonna is the centre figure and is larger than any of the others to signify her importance. Christ sits on her knees, eating grapes offered to him by his mother. 

Luke 1:26 And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth, ²⁷ To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin's name was Mary. ²⁸ And the angel came in unto her, and said, Hail, thou that art highly favoured, the Lord is with thee: blessed 'art' thou among women. ²⁹ And when she saw him, she was troubled at his saying, and cast in her mind what manner of salutation this should be. ³⁰ And the angel said unto her, Fear not, Mary: for thou hast found favour with God. ³¹ And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name Jesus. ³² He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: ³³ And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end. ³⁴ Then said Mary unto the angel, How shall this be, seeing I know not a man? ³⁵ And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God. ³⁶ And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. ³⁷ For with God nothing shall be impossible. ³⁸ And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her.

The calendar of religious holidays

For the calendar of religious holidays and periods, see Liturgical year. For this year's Gregorian calendar, see Leap year starting on Sunday.

The Gregorian reform contained two parts: a reform of the Julian calendar as used prior to Pope Gregory's time and a reform of the lunar cycle used by the Church, with the Julian calendar, to calculate the date of Easter. The reform was a modification of a proposal made by the Calabrian doctor Aloysius Lilius (or Lilio).[5] Lilius's proposal included reducing the number of leap years in four centuries from 100 to 97, by making 3 out of 4 centurial years common instead of leap years: this part of the proposal had been suggested before by, among others, Pietro Pitati. Lilio also produced an original and practical scheme for adjusting the epacts of the moon when calculating the annual date of Easter, solving a long-standing obstacle to calendar reform.

The Gregorian calendar, also called the Western calendar and the Christian calendar, is internationally the most widely accepted civil calendar.[1][2][3] It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582; the decree, a papal bull, is known by its opening words, Inter gravissimas.[4] The Gregorian calendar was adopted later that year by a handful of countries, with other countries adopting it over the following centuries.

The motivation for the Gregorian reform was that the Julian calendar assumes that the time between vernal equinoxes is 365.25 days, when in fact it is presently almost 11 minutes shorter. The discrepancy results in a drift of about three days every 400 years. At the time of Gregory's reform there had already been a drift of 10 days since Roman times, resulting in the spring equinox falling on 11 March instead of the ecclesiastically fixed date of 21 March, and moving steadily earlier in the Julian calendar. Because the spring equinox was tied to the celebration of Easter, the Roman Catholic Church considered this steady movement in the date of the equinox undesirable.

Saint Anne by Federico Cantu

Saint Anne (also Ann or Anna, from Hebrew Hannah חַנָּה, meaning "favor" or "grace") of David's house and line, was the mother of the Virgin Mary and grandmother of Jesus Christ according to Christian and Islamic tradition. Mary's mother is not named in the canonical gospels or the Qur'an, and her name and that of her husband Joachim come only from New Testament apocrypha, of which the Protoevangelium of James, written perhaps around 150, seems to be the earliest that mentions them.