 When Christmas Day is a Monday, Advent Sunday will fall on its latest possible date.In the Ambrosian Rite and the Mozarabic Rite of the Catholic Church, Advent begins on the sixth Sunday before Christmas, the Sunday after St. Martin's Day ().Practices associated with Advent include keeping an Advent calendar, lighting an Advent wreath, praying an Advent daily devotional, erecting a Christmas tree or a Chrismon tree, lighting a Christingle, as well as other ways of preparing for Christmas, such as setting up Christmas decorations, a custom that is sometimes done liturgically through a hanging of the greens ceremony.