Date of birth of Jesus

Estimation via the Nativity accounts

The nativity accounts in the New Testament gospels of Matthew and Luke do not mention a date or time of year for the birth of Jesus, and Karl Rahner states that the gospels do not in general provide enough details of dates to satisfy the demands of modern historians. Mainstream scholars do not see the Luke and Matthew nativity stories as historically factual, and for this reason they do not consider them a reliable method for determining Jesus’ date of birth. Karl Rahner states that the authors of the gospels generally focused on theological elements rather than historical chronologies.

Both Luke and Matthew associate Jesus' birth with the time of Herod the Great. Matthew 2:1 states that "Jesus was born in Bethlehem of Judaea in the days of Herod the king". He also implies that Jesus could have been as much as two years old at the time of the visit of the Magi, because Herod ordered the murder of all boys up to the age of two years, “in accordance with the time he had learned from the Magi”. Matthew 2:16 Most scholars agree that Herod died in 4 BC, although a case has also been made that Herod died only in 1BC.

Luke 1:5 mentions the reign of Herod shortly before the birth of Jesus, but places the birth during the Census of Quirinius, which only took place ten years later in 6 AD as described by the historian Josephus. The Jewish historian Josephus, in his Antiquities of the Jews (ca. AD 93), indicates that Cyrenius/Quirinius' governorship of Syria began in AD 6, and Josephus mentions a census sometime between AD 6–7.

Most scholars believe Luke made an error in referring to the census. Raymond E. Brown notes that "most critical scholars acknowledge a confusion and misdating on Luke's part." As a result, most scholars generally accept a date of birth between 6 and 4 BC, the year in which Herod died. Tertullian believed some two centuries later that a number of censuses were performed throughout the Roman world under Saturninus at the same time. However some conservative Christian biblical scholars and commentators still believe the two accounts can be harmonised, arguing that the text in Luke can be read as "registration before Quirinius was governor of Syria", i.e. that Luke was actually referring to a completely different census. Geza Vermes has described such approaches as 'exegetical acrobatics'.

Working backwards from when Jesus began preaching

Another approach to estimating the year of birth works backwards from when Jesus began preaching, based on the statement in Luke 3:23 that he was "about 30 years of age" at that time. Jesus began to preach after being baptised by John the Baptist, and based on Luke’s gospel John only began baptising people in "the fifteenth year of the reign of Tiberius Caesar" (Luke 3:1–2), which scholars estimate would be in about AD 28–29. By working backwards from this, it would appear that Jesus was probably born no later than 1 BC. However, if the phrase "about 30" is interpreted to mean 32 years old, this could fit a date of birth just within the reign of Herod, who died in 4 BC.

This date is independently confirmed by John's reference in John 2:20 to the Temple being in its 46th year of construction during Passover when Jesus began his ministry, which corresponds to around 27–29 AD according to scholarly estimates.

Christmas celebration

Despite the celebration of Christmas in December, neither Luke nor Matthew mentions a season for when Jesus was born. However, scholarly arguments regarding the realism of shepherds grazing their flock during the winter have taken place, both challenging a winter birth for Jesus as well as defending it by relying on the mildness of winters in ancient Israel and rabbinic rules regarding sheep near Bethlehem before February.

The celebration of Christmas as the birth day of Jesus is based on a date of a pagan feast rather than historical analysis. Saturnalia, the Roman feast for Saturn was associated with the winter solstice (between Dec 21st and 23th in northern hemisphere). Saturnalia was held on 17 December of the Julian calendar and later expanded with festivities through to 23 December. The holiday was celebrated with a sacrifice at the Temple of Saturn, in the Roman Forum, and a public banquet, followed by private gift-giving, continual partying, and a carnival atmosphere that overturned Roman social norms.

In the 1st and 2nd centuries, the Lord's Day (Sunday) was the earliest Christian celebration and included a number of theological themes. In the 2nd century, the Resurrection of Jesus became a separate feast as Easter and in the same century Epiphany began to be celebrated in the Churches of the East on 6 January. The festival of the Nativity which later turned into Christmas was a 4th-century feast in the Western Church notably in Rome and North Africa, although it is uncertain exactly where and when it was first celebrated.

The earliest source stating 25 December as the date of birth of Jesus is likely by Hippolytus of Rome, written very early in the 3rd century, based on the assumption that the conception of Jesus took place at the Spring equinox which he placed on March 25, and then added nine months – festivals on that date were then celebrated. John Chrysostom also argued for a 25 December date in the late 4th century, basing his argument on the assumption that the offering of incense in Luke 1:8–11 was the offering of incense by a high priest on Yom Kippur (early October), and, as above, counting fifteen months forward. However, this was very likely a retrospective justification of a choice already made rather than a genuine attempt to derive the correct birth date.