Retablos, from "retablo", which is literally translated "behind the altar," are small, multi-paneled oil paintings on wood depicting Christ, the Virgin Mary, or any one of the multitude of Catholic saints. Ex-votos, from the Latin "from a vow," are paintings on tin or canvas offered as thanks to particular saints who have helped an individual in a specific way.
~from The Daily Book of Art
Did you know that New Mexico State University has the largest public collection of retablos in the U.S.? To visit their collection online, click here.
Also check out Mexican Retablos, a unique website dedicated to retablo art, ex-votos, Mexican folk, Spanish colonial and more; Peruvian Folk Art Retablos; Ex-Votos from Mexico; Everyday Miracles: Ex-Votos Anatomy; & Milagre Ex-votos from Northeast Brazil for more examples of these arts.
To view the library sysyem's holdings on retablos, do a keyword search using the word retablo(s); or a subject heading search under Altarpieces.