Sacred Bones is based on the true story of Deusdona (“God’s gift”), a ninth-century Roman deacon who worked in the catacombs, digging up worthless bones and selling them off as the holy remains of saints and martyrs. Deusdona thanked God for his worldly success, but he was also a clever businessman who knew how to strike deals with abbots and kings. It didn’t hurt that no church could be sanctified without a relic in residence, and that the more relics a...