Las Posadas, 16 December

Las Posadas runs nine nights from the sixteenth of December through Christmas Eve, the span this rule records, reenacting each evening Mary and Joseph's search for lodging, posada, in Bethlehem before Jesus's birth. The custom is a colonial era Catholic devotion, introduced into New Spain by missionaries, generally credited to Augustinian friars working in the sixteenth century, who adapted the nine day devotional structure of an existing Catholic novena to a dramatized, participatory form better suited to catechizing an Indigenous population than a purely liturgical Latin service would have been, one of many examples of missionary practice reshaping an inherited European custom for a new context rather than transplanting it unchanged.

Each night, participants process from house to house carrying images of the holy family and asking for shelter in song, traditionally refused at several doors before being welcomed at the final one, followed by prayers, food and often the breaking of a pinata, a festive element added to the devotion over time rather than part of its original catechetical design. The nine nights conclude on Christmas Eve itself, folding directly into that night's own celebrations, and the custom remains most strongly associated with Mexico and other parts of Latin America, carried into diaspora communities across North America as a distinctly Mexican Advent season observance.