The Sanctuary of Santa Maria della Quercia is the most important sanctuary in the province of Viterbo. Its story begins in 1417 when master Battista Luzzante had the image of the Virgin Mary painted on a flat tile by a painter called Monetto who was then hung from an oak tree. The beginning of the cult of the Madonna della Quercia began in 1467 when a knight pursued by his enemies threw himself at the foot of the oak where the sacred image was hung and miraculously became invisible to his pursuers; according to others, it dates back to a plague that devastated Upper Lazio in that same year and 30,000 devotees ran under the oak to invoke mercy and after a week of prayer the plague ceased. Following these events, between 1467 and 1469, it was decided to build a church and then built the first Sanctuary. Thanks to the Dominican Fathers who considered her their protector, the cult of the Virgin of the Oak grew more and more and expanded throughout Italy and also in Europe. Inside the sanctuary we can admire the coffered ceiling covered in gold designed by Antonio da Sangallo and the marble temple by Andrea Bregno that contains the miraculous tile. Also beautiful are the cloister and the former convent built on a project by Giuliano da Sangallo. The three entrance portals are surmounted by terracotta lunettes, the work of Andrea Della Robbia: the central lunette depicts the Madonna della Quercia, the two lateral ones San Pietro and San Tommaso D'Aquino. Ghirlandaio's frescoes on the sides of the temple and some other frescoes from the school of Sebastiano del Piombo.