The consensus of scholars is that both gospels were written about AD 75-85, and while it is possible that Matthew's account might be based on Luke, or Luke's on Matthew, the majority conclusion is that the two are independent of each other.
In Christian theology the nativity marks the birth of Jesus in fulfillment of the divine will of God, to save the world from sin. The artistic depiction of the nativity has been an important subject for Christian artists since the 4th century. Since the 13th century, the nativity scene has emphasized the humility of Jesus and promoted a more tender image of him, as a major turning point from the early "Lord and Master" image, mirroring changes in the common approaches taken by Christian pastoral ministry.
Christians of the Eastern Orthodox Church and Oriental Orthodox Church observe a similar season, sometimes called Advent but also called the "Nativity Fast", which begins forty days before Christmas. Some Eastern Orthodox Christians (e.g. Greeks and Syrians) celebrate Christmas on December 25. Other Orthodox (e.g. Copts, Ethiopians, Georgians, and Russians) celebrate Christmas on (the Gregorian) January 7 (Koiak 29 on coptic calendar) as a result of their churches continuing to follow the Julian calendar, rather than the modern day Gregorian calendar.
The date of birth for Jesus of Nazareth is not stated in the gospels or in any secular text, but a majority of scholars assume a date of birth between 6 BC and 4 BC. The historical evidence is too ambiguous to allow a definitive dating, but the date is estimated through two different approaches — one by analyzing references to known historical events mentioned in the Nativity accounts in the Gospels of Luke and Matthew, and the second by working backwards from the estimation of the start of the ministry of Jesus.