There is one church on the piazza that was actually built for religious reasons, Santa Maria del Popolo. Nero's ashes were buried on this site, which the superstitious Romans came to believe became haunted by Nero's ghost. In 1100, the pope performed an exorcism of the site, and to reinforce the effect, had this church built on top of the previously haunted site. The church became a favorite of the aristocracy, who added elaborate private chapels to the main church where they could worship apart from the hoi polloi. They tried to outdo one another in the extravagance of these chapels, making the church the repository of a wealth of Renaissance art.