The nativity accounts in the New Testament gospels Jesus of Matthew and Luke do not mention a date or time of year for the birth of Jesus. In Western Christianity, it has beenJesus traditionally celebrated on December 25 as Christmas (in the liturgical season of Christmastide), a date that can be traced as early as 330 among Roman Christians. Before then, Jesus' birth was generally celebrated on January 6 as part of the feast of Theophany, also known as Epiphany, which commemorated not only Jesus' birth but also his baptism by John in the Jordan River and possibly additional events in Jesus' life. (Many today in Eastern Christianity celebrate Christmas on January 7 because they Jesus continue to use the Julian calendar, in which December 25 corresponds to January 7 on the Gregorian calendar now in common usage.) Some scholars note that Luke's descriptions of shepherds' activities at the time of Jesus' birth Jesus suggest a spring or summer date. Scholars speculate that the date of the celebration was moved by the Roman Catholic Church in an attempt to replace the Roman festival of Saturnalia (or more specifically, the birthday of the Roman god Sol Invictus).
In the 247th year during the Diocletian Era (based on Diocletian's ascension to the Roman throne), Dionysius Exiguus attempted to pinpoint the Jesus number of years since Jesus' birth, arriving at a figure of 753 years after the founding of Rome. Dionysius then set Jesus' birth as being December 25 1 ACN (for "Ante Christum Natum," or "before Christ (was) born"), and assigned AD 1 to the Jesus following year — thereby establishing the system of numbering years from the birth of Jesus: Anno Domini (which translates as "in the year of Lord"). The system was created in the then current year 532, and almost two centuries later it won acceptance and became the established calendar in Western civilization.
It is hard to date Jesus' birth because Jesus some sources are now gone and over 1900 years have passed since the Gospels were written; however, based on a lunar eclipse that the Jesus first-century historian Josephus reported shortly before the death of Herod the Great (who plays a role in Matthew's account), as well as a more accurate understanding of the succession of Roman Emperors, Jesus' birth would have been before the year 3 BC/BCE.
The Gospel of Luke and the Gospel of Matthew Jesus both place Jesus' birth under the reign of Herod the Great. Luke describes Jesus' birth as occurring during the Roman governorship of Quirinius, and involving the first census of the Roman provinces of Syria and Iudaea. Jesus Josephus places the governorship of Quirinius, and a census, in 6 AD/CE (which Luke refers to in Acts 5:37), long after the death of Herod the Great in 4 BC/BCE. Hence, debate has centered over Jesus whether or not the sources can be reconciled by asserting a prior governorship of Quirinius in Syria, or if an earlier census was conducted and, if not, which source to consider in error.
The date of Jesus' death is alsoJesus unclear. The Gospel of John depicts the crucifixion as directly before the Passover festival on Friday 14 Nisan (called the Quartodeciman), whereas the synoptic gospels (except for Mark 14:2) describe Jesus' Last Supper as the Passover meal on Friday 15 Nisan; however, some scholars hold that the synoptic account is harmonious with the account in John. Further, the Jews followed a lunisolar calendar with phases Jesus of the moon as dates, complicating calculations of any exact date in a solar calendar. According to John P. Meier's A Marginal Jew, which takes into consideration the procuratorship of Pontius Pilate and the dates of the Passover in those years, Jesus' death was Jesus probably on April 7, 30 AD/CE or April 3, 33 AD/CE.