There are many theories as to how the Church determined when to celebrate the birth of the Christ. Here is another one.

This is the time of year when we hear of arguments being raised against the display of nativity scenes in public places and the substitution of generic holiday greetings for ‘Merry Christmas’ in department stores and retail outlets. Initially, the argument was based on the constitutional separation of church and state, but motivated by an exaggerated fear of offending non-believers, the celebration of Christmas has been under attack. Even some practicing Christians have begun to retreat from celebrating Christ’s birth on December 25th because they have been told that the origins of Christmas are pagan and have nothing at all to do with God sending His Son.

Perhaps it is time that the full truth were known.

It is not exactly true to say that the Scriptures never mention the date of the birth of Jesus. Actually they do, since the Gospels of Matthew, Mark and Luke all make it clear that Jesus died on the 14 of Nissan, a day which corresponded to March 25th in the Latin calendar or April 6 in the reckoning of the Greeks. The ancients believed that a person died on the day which marked his or her conception, and this is one reason why the Church celebrates the feast of Our Lord’s conception - the Annunciation - on March 25th and then counts nine months to His birth. This is also why the Eastern Catholic Churches celebrate the birth of Christ on January 6th, while we commemorate his Epiphany.

Do the Gospels contain any other information which would help us calculate when Christ was born? Indeed they do and while this may read somewhat like a mystery, if you follow closely you will gain a great insight.

First, turn to St. Luke’s Gospel, to the passage referred to as the ‘Canticle of Zechariah,’ in 1:5-24. The story tells of a high priest named Zechariah who had been chosen to offer the sacrifice of incense in the temple at Jerusalem. Outside, St. Luke tells us, the people were waiting for the priest to make his appearance, but inside the angel Gabriel appears to Zechariah to tell him that his prayer has been answered. Gabriel goes on to say that Zechariah and his elderly wife Elizabeth will conceive and bear a son, whom they are to name ‘John.’

Catholics are familiar with this story and remember that when the Angel’s promise comes to pass Zechariah and Elizabeth become the parents of John the Baptist. What most people fail to realize is that St. Luke has given us some important clues in his story concerning the birthday of Jesus. What Zechariah is celebrating in the Holy of Holies of the Temple is the Jewish Day of Atonement, called Yom Kippur. Even today on Yom Kippur, one week after Rosh Hoshanah, the Jewish New Year, pious Jews the world over will ask God to release them from their sins . Rosh Hoshanah generally falls in early to mid September (counting 183 days from Passover), so Yom Kippur falls in mid September, about the 21st of the month (although it can be as late as October).

Continuing to read in Luke (1:26-56) we come to the Annunciation of Our Lord, when Gabriel appears to the Virgin Mary, asking her to cooperate in the most significant event is history: the birth of Our Savior Jesus. Much can and has been written of this, but of relative importance to our question about when Christ was born is Luke’s note that this second annunciation occurred six months after Elizabeth had become pregnant.

Now this is where your math skills come in handy! Elizabeth conceives around September 21st and six months later is March 21st. This is the date that Mary conceives. The length of a woman’s pregnancy is 40 weeks, or 9 months and a couple of days. Add nine months and a couple of days to the date of Our Lord’s Annunciation in mid-March and we arrive at December 25th, Christmas Day, a date, which confirms the calculations made working backwards from the date of Our Lord’s crucifixion.

These were the same calculations that the early Church made when they chose December 25th for the annual celebration of the birthday of Jesus. While the pagan Romans were celebrating their feast of Saturn (the Saturnalia) from December 13th through the 18th, the Christians in the empire were preparing for a much more important celebration one week after the end of Saturnalia.

Romans celebrated no holiday on December 25th until the last quarter of the third century when Diocletian (Emperor from 284 to 305) made that day the “Feast of the Unconquerable Sun.” (Some scholars believe this was the work of Diocletian’s predecessor Aurelian.) Since there is clear evidence that Christmas was already being celebrated in the principal cities of the western empire, Diocletian’s new feast must have been meant to usurp the Christian holy day by turning the day into a pagan feast and a civic holiday.

Thus it was not the Catholic Church that introduced a pagan celebration into Christianity; but the pagans who attempted to usurp a Christian holy day. And now, as we hear it said, “you know the rest of the story