The Western Christian liturgical year begins with the first Sunday of Advent. Western churches set that Sunday as the one closest to the feast of St. Andrew (November 30), while Eastern Christians begin a period of fast in preparation for Christmas on the feast of St. Philip (November 14). For most Christians, four Sundays mark this season of waiting and expectation of the birth of Christ. Christmas, the celebration of Jesus’ birth, was originally fixed on December 25 around the year 336. That was the date then calculated as the winter solstice on the Roman calendar, with its symbolic celebration of the rebirth of the sun after the year’s darkest day. In the practice of the liturgical churches, purple vestments still recall the originally penitential spirit of the season, with its overtones of apocalyptic expectation of Christ’s second coming. But on the third Sunday, called Gaudete (“Rejoice”) Sunday, rose vestments introduce a note of relief. Christmas represents for all Christians the pivotal event in human history called the Incarnation, in which God took on human flesh and assumed all aspects of the human condition except sinfulness.