There was a time when Christians did not celebrate a season that could be called the 30-something days of Christmas.

In the year of our Lord 1939, the National Retail Dry Goods Association asked President Franklin D. Roosevelt to move Thanksgiving to the next-to-last Thursday in November. This was strategic, since President Abraham Lincoln had proclaimed the last Thursday of the month as the official holiday. This meant that Thanksgiving was occasionally delayed until a fifth Thursday -- a cruel blow to merchants.

Confusion reigned until Congress reached a compromise and, since 1942, Thanksgiving has been observed on the fourth Thursday in November.

And thus was born America's most powerful and all-consuming season. This later evolved into the shopping festival called "The Holidays," which in the past generation has started creeping into stores days or weeks before Turkey Day.

"None of this, of course, has anything to do with the Christmas traditions that Christians have been observing through the ages," said Teresa Berger, professor of liturgical studies at Yale Divinity School.

To be candid, she said, it does "help to remember that celebrations of Christmas and other holy seasons have always been affected by what happens in the marketplace and the surrounding culture. ... But that isn't what we are seeing, today. The question now is whether or not the shopping mall will define what is Christmas for most Christians."

Here's the bottom line. For centuries, Christmas was a 12-day season that began on Dec. 25th and ended on Jan. 6th with the celebration of the Feast of the Epiphany. Thus, the season of Christmas followed Christmas Day, with most people preparing for the holy day in a festive blitz during the final days or even hours, with many stores staying open until midnight on Christmas Eve.

Today, everything has been flipped around, with the Christmas or Holiday season preceding Dec. 25.

For most Americans, this season begins with an explosion of shopping on Black Friday after Thanksgiving, followed by a flurry of office parties and school events packed into early December. The goal is to hold as many of these events as possible long before the onset of the complicated travel schedules that shape the lives of many individuals and families.

Meanwhile, television networks, radio stations and newspapers have created their own versions of the "12 days of Christmas," inserting them before -- often long before -- Dec. 25 as a secular framework for advertising campaigns, civic charity projects, holiday music marathons, parades, house-decorating competitions and waves of mushy movies, old and new.

Needless to say, this is not the Christmas that Berger knew as she grew up in Germany in the post-World War II era. As a Catholic, the days between Christmas and Epiphany were marked by a series of events -- such as the feasts of St. Stephen and St. John the Evangelist -- that were accompanied by their own rites and customs. Lutherans and other Christians had their own traditions for marking this time.

"When people talk about a season called the 'Twelve Days of Christmas,' they are primarily talking about something that was much more common in England," said Berger. "There are many reasons for that, not the least of which was the popularity of the song by that name."

While these traditions took various forms, the key was that the religious elements of the season remained intact. Christians celebrated Christmas during Christmas.

Berger said that it still makes her a bit uncomfortable when she sees families putting up and decorating their Christmas trees before they are even finished using the candles and green wreathes associated with the penitential season of Advent, which begins on the fourth Sunday before Christmas. There are many more people, of course, who do not observe Advent, which is called Nativity Lent in Orthodox churches.

"Today, people believe they can have whatever they want, when they want it, and Christmas becomes whatever the culture says that it is," she said. "We can, however, revolt against this. We can choose, for example, not to send out 1,000 mindless Christmas cards. We can sit down and write our own cards and even breathe a prayer for the people we love while we do that.

"No one can force us to live according to the laws of the new Christmas. We can make our own choices."