Here's a thought for the harried among us who are unready for the arrival of another Christmas season: There was a time when some scholars argued that the holiday should be observed in the spring. Just imagine three more months of shopping!

  It seems to us a matter of course that Christmas should come on Dec. 25. But over the past 2,000 years or so, the timing of Jesus' birth - which, as the bumper stickers like to remind us, is the original reason for the season - has generated considerable controversy. In fact, there has been enough uncertainty about when to celebrate Jesus' birthday that some Christians have chosen not to celebrate it at all.

 The Bible offers little help in resolving the question: No dates are offered in the Gospel stories. There isn't even a reference to the season of the year. Some readers have thought they detected a clue in the evangelist Luke's mention of shepherds tending their flocks at night as they hear the news of Jesus' birth. To some, this suggests not a December birth, but one during the spring lambing season, when the animals would be free to roam out of their corrals. But wait: Advocates for a December Nativity answer that sheep reserved for temple sacrifices would have grazed unfettered even in deepest winter.

 Clearly, any dispute that hinges on knowledge of Middle Eastern livestock practices of antiquity is not going to be resolved easily.

  Why should it matter? The earliest Christian writers were more interested in Jesus' death and resurrection than in his birth. The oldest of the Gospels, Mark's, makes no mention of Jesus' birth. Later, Matthew and Luke offered extravagant detail - stars, wise men, mangers - but no specifics about timing.

 This didn't stop others from making their own guesses. The theologian Clement of Alexandria, writing around 200, mentions some of the dates that had by then already been proposed as the true date of Jesus' birth. Spring Nativities were popular, with dates in May, April and March being proposed. Dec. 25 was not mentioned as a possibility.

 So how did we end up celebrating a wintry white Christmas? The church only settled on a Dec. 25 Christmas in the fourth century. The standard explanation is that the early church conflated its celebration of the Nativity with pre-existing pagan festivals. Romans had their Saturnalia, the ancient winter festival, and northern European people had their own solstice traditions. Among the features: parties, gift-giving, dwellings decorated with greenery.

 The reasoning goes that the growing church, recognizing the popularity of the winter festivals, attached its own Christmas celebration to encourage the spread of Christianity. Business historian John Steele Gordon has described the December dating of the Nativity as a kind of ancient-world marketing ploy.

But some put forward another, less well-known explanation for the Dec. 25 date - one with appeal for anyone uncomfortable with a connection between Christmas and the old solstice festivals. According to some scholars, Christmas was set near the winter solstice not because of any pagan traditions but based on a series of arcane calendrical computations. This argument hinges on an ancient Jewish tradition that had the great prophets dying on the same dates as their birth or, alternatively, their conception. Thus, to follow this peculiar assumption, the first step in dating Jesus' birth would be to date his death, which the Gospels say happened at Passover. The early Christian writer Tertullian calculated that the date given for Jesus' death in John's Gospel corresponds to March 25 in the Roman calendar. Many Christian churches came to celebrate the Feast of the Annunciation, marking the angel Gabriel's visit to the Virgin Mary to tell her that she would become the mother of Jesus, on this date. Adding nine months to this date produces a Dec. 25 Christmas.

This alternative explanation is sometimes deployed to dismiss the notion that the holiday had pagan roots. In a 2003 article in the journal Touchstone, for example, historian William Tighe called the pagan origin of Christmas "a myth without historical substance." He argued at least one pagan festival, the Roman Natalis Solis Invictus, instituted by Emperor Aurelian on Dec. 25, 274, was introduced in response to the Christian observance. The pagan festival "was almost certainly an attempt to create a pagan alternative to a date that was already of some significance to Roman Christians." According to Tighe, the pagans co-opted the Christian holiday, not the other way around.

But even to some Christians, Christmas has always seemed like a version of a pagan feast - and therefore unworthy of observance. The early church father Origen argued against celebrating Jesus' birthday: "It is only sinners like Pharaoh and Herod who make great rejoicings over the day on which they were born into this world." The Puritans of 17th-century Massachusetts famously banned the holiday, in part because they found no Biblical authority for celebrating the Nativity on Dec. 25. (They also feared the Saturnalia-esque disorder and rowdiness that seemed to go with the holiday.) Quakers, too, abstained from celebrating. Harriet Beecher Stowe has a character in her 1878 novel "Poganuc People" explain why his family doesn't observe Christmas: "Nobody knows when Christ was born, and there is nothing in the Bible to tell us when to keep Christmas."

There is something familiar about all these erstwhile Christmas controversies. The holiday is still prime time for disputation. At this time of year, more than any other, the sacred and the secular spend a lot of time jostling for space, and eventually, accommodating each other. So, believers need not be threatened by Christmas' putative pagan roots. If the church repurposed the old solstice feasts, it only goes to show its power to bend the broader culture to its pastoral purpose.