Posadas are an important part of Mexican Christmas traditions.
These community celebrations take place on each of the nine nights leading up to Christmas, from December 16 to 24th. The word posada means "inn" or "shelter" in Spanish, and in this tradition, Mary and Joseph's journey to Bethlehem and their search for a place to stay is re-enacted.
Posadas are held in neighborhoods across Mexico and are also becoming popular in the United States. The celebration begins with a procession in which the participants hold candles and sing Christmas carols. Sometimes there will be individuals who play the parts of Mary and Joseph who lead the way, or occasionally images representing them are carried. The procession will make its way to a particular home (a different one each night), where a special song (La Cancion Para Pedir Posada) is sung.
Asking For Shelter
There are two parts to the traditional posada song. Those outside the house sing the part of Joseph asking for shelter and the family inside responds singing the part of the innkeeper saying that there is no room.
The song switches back and forth a few times until finally the innkeeper decides to let them in. The hosts open the door and everyone goes inside.
Once inside the house there is a celebration which can vary from a very big fancy party to a small get-together among friends. Often the festivities begin with a short Bible reading and prayer. Then the hosts give the guests food, usually tamales and a hot drink such as ponche or atole. Then the guests break piñatas and the children are given candy.
The nine nights of posadas leading up to Christmas are said to represent the nine months that Jesus spent in Mary's womb, or alternatively, to represent nine days journey to Bethlehem.
History of the Posadas
Now widely-celebrated tradition throughout Latin America, posadas originated in colonial Mexico. The Augustinian friars of San Agustin de Acolman, near Mexico City are believed to have celebrated the first posadas. In 1586, Friar Diego de Soria, the Augustinian prior, obtained a papal bull from Pope Sixtus V to celebrate what were called misas de aguinaldo "Christmas gift masses" between December 16 and 24.
The Aztecs had a tradition of honoring their god Huitzilopochtli at the same time of year (coinciding with the winter solstice), and they would have special meals in which the guests were given small figures of idols made from a paste that consisted of ground toasted corn and agave syrup. The friars took advantage of the coincidence and the two celebrations were combined.
The celebrations were originally held in the church, but the custom spread and later was celebrated in haciendas, and then in family homes, gradually taking the form of the celebration as it is now practiced by the 19th century.
Source: Go Mexico