Retablo

A retablo in Mexican folk art (also lámina) is a devotional painting, especially a small popular or folk art one using iconography derived from traditional Catholic church art. Throughout Ibero-America and Catholic countries such as the Philippines, the word is used in its original context, where retablo is close to the English reredos or retable in French, meaning a decorated vertical structure rising behind the altar of a church. Typically this includes painting, sculpture or a combination of the two, and an elaborate framework enclosing it. The Latin etymology of the Spanish word means "board behind". Aside from being found behind the altar, "similar ornamental structures are built and carved over facades and doorways" (Fernandez 23), called overdoors.

Small retablos are devotional or votive paintings, often on rectangular sheets of tin that illustrate holy images such as Christ, the Virgin Mother, or one of the hundreds of saints. Many are ex-votos ("from a vow") that depict the story that led to their commission, usually dangerous or threatening events that actually occurred, and which the person survived, thanks to the intercession of a sacred person - God, Mary or a saint. They are made as a way of thanking the sacred person for protection in precarious situations, such as surviving an illness or earthquake. This class of ex-votos often shows the protected humans in the dangerous situation, and the sacred person who protected them, usually with an inscribed explanation of the events, with the date and location. Both devotional and especially ex-voto retablos may be deposited at a shrine as a votive offering, or alternatively kept at home.

Reredos of the Late Middle Ages and Renaissance in Spain grew extremely large and elaborate, typically using carved and gilded wood, and rising as high as 40 feet or more. The tradition of making them was taken to the new Spanish Empire in America. There, by the late 18th century at least, the word became used for much smaller popular religious paintings, both conventional devotional images and ex-votos (paintings giving thanks for protection through a specific episode). These were typically made to express gratitude towards the Virgin Mary for saving a person or a loved one from a nearly fatal event.

...
Wikipedia