Historical documentation of the Casa de Rayas is scarce, as is the case with many colonial era houses. A plaque at the entrance to the building dates the house to1697, though it may well have been built at an earlier date. We do know that by the late 17th century the Sardoneta family owned the home. As owners of the Rayas silver mine, the Sardoneta family became one of the richest families in Mexico. By the18th century the family had become titled nobility, and the house was known as the House of the Marquises de Rayas (La Casa de los Marqueses de Rayas). In 1776 the family built a private chapel on the second floor of the mansion with an impressive Churrigueresque portal and retablo, both designed by architect Felipe de Ureña. The altarpiece was sold in the early 1920's and now resides at the Mission Inn in Riverside, California. The Casa de Rayas has become the city museum of the city of Guanajuato, and the chapel now functions as a small auditorium. Mexican muralist José Chávez Morado was commissioned to paint the walls of the onetime chapel with modern frescos.