No doubt about it, 25 minus 12 does equal 13.

Christmas is Dec. 25th. Lovers of carols and party games also know this season has 12 days, packed with pears, gold rings, birds and various kinds of gentry, musicians and domestic workers.

Do the math. It's easy to see why many leaders of newspapers, television networks, shopping malls and other cultural fortresses annually deliver some kind of "Twelve Days Of Christmas" blitz beginning on Dec. 13.

But there's a problem. There really are 12 days of Christmas and, for centuries, church calendars in the East and West have agreed that they begin on Christmas and end on Jan. 6, the Feast of the Epiphany.

"Somebody needs to teach Bryant Gumbel and all the other Powers That Be some church history. They keep getting it wrong," said Father Patrick Henry Reardon, a philosophy professor and priest at St. Anthony's Orthodox Church in Butler, Pa. "If saying that upsets people, so be it. Orthodoxy has been in the business of upsetting people for centuries. ... But there isn't a bit of doubt that the 12 days of Christmas come after Dec. 25."

Journalism's bible -- the Associated Press Stylebook -- is agnostic on this matter. It merely notes that Christmas is a federal holiday observed on Dec. 25 or on "Friday if Dec. 25 falls on a Saturday, on Monday if it falls on a Sunday." There are no entries for the penitential season of Advent, the four weeks preceding Christmas, or Epiphany.

The latter feast -- the name means "manifestation" -- probably began in the second century. In the East, this initially included references to the birth of Jesus, along with other signs of the incarnation. Meanwhile, the Western church in Rome developed its own Nativity feast and timed it, for various reasons, to co-opt the date used for pagan celebrations of the Winter Solstice or the feast of Sol Invictus, the "Unconquered Sun."

A sermon by St. John Chrysostom in 386 A.D. notes that the East had recently begun celebrating Christmas on Dec. 25 and, about the same time, the West adopted Epiphany. This liturgical exchange created a 12-day celebration, a sacred and secular festival after the quiet season of Advent, or "Winter Lent." However, note that Advent does include one festive date -- the Dec. 6 feast honoring St. Nicholas of Myra.

Different cultures celebrated in different ways, but the basic season -- Advent, Christmas and Epiphany -- remained intact. The Protestant Reformation complicated matters and, in the New World of America, the Puritans actually banned Christmas celebrations. Later, waves of immigrants arrived with their religious traditions, especially Italian Catholics and German Lutherans. But this did little to change the civic and commercial nature of the American season. Another pivotal event was the 1822 publication of "A Visit From St. Nicholas," written by a Clement Clarke Moore, a powerful New York Episcopalian.

"Actually, the Dutch already had brought us a secularized St. Nicholas and everything that went along with him," said Evelyn Vitz of New York University, author of "A Continual Feast," a cookbook and theological commentary on the Christian calendar. "But you throw in this amazing mythology created by Moore's poem -- this kind of jolly, pagan elf up on the roof -- and ... you end up with an entire season that has been commercialized and stripped of its larger Christian context."

The big question: What can parents and churches do? Meditations on centuries of Christian tradition can easily be drowned out by the clamor of popular culture. Americans clearly prefer the rites of Madison Avenue to those of Rome or Jerusalem.

"We live in this culture. Our children live in this culture. We can fight, I guess," said Vitz. "We can go so far that we make everybody in our families so miserable that they want to quit being Christians. But it is clear that we can't accept business as usual. We need to recapture a sense of time and a sense of the sacred. We can start by insisting that the church's calendar really matters."