premise: Its prized possessions are the haunting Volto Santo (Holy Face), a wooden crucifix said to have been carved by Nicodemus and possessing miraculous powers; and the graceful white marble tomb of Ilaria del Carretto Guinigi by master Sienese sculptor Jacopo de lla Quercia (1408) in the former sacristy.
hypothesis: A wooden crucifix is its prized possession. 