One thousand five hundred years ago, people in France started preparing for Christmas on November 11th, the Feast of St. Martin of Tours. They weren't busy shopping, but they prepared for fasting 3 times a week. A century later, Christians were fasting every day, seven days a week from November 11 until December 25th. That was known as St. Martin's Lent. The practice spread. As far as we know this may have been the beginning of Advent.
Many still remember that Advent was a time to do penance or give up things to prepare for Jesus' birth. Often we went to Confession at that time to be prepared better spiritually. Our world is so different now. The aspect of spiritual preparation has slipped into the background while we busy ourselves with so many other projects that we have to finish by December 25th. Sometimes I ask myself, if those who are trying to get Christ out of Christmas are winning, because in our world today, if Christ plays any part at all in our preparations for his birth, it is only a minor part.