(Latin adventus, “coming”), in the Christian ecclesiastical calendar, a season observed in preparation for Christmas. The earliest authentic record of Advent (ad 581) states that the season starts on the feast of St. Martin, November 11; this period is still observed in the Orthodox church. About 600, Pope Gregory I decreed that the season should start on the fourth Sunday before Christmas, but the longer period was observed in England for some years. The shorter period is now observed in the Roman Catholic, Lutheran, Anglican, Presbyterian, and Episcopal churches, and the first Sunday of Advent is regarded as the commencement of the Christian ecclesiastical year. The season is also a preparation for the second coming of Christ at the end of the world.