Asterius of Ostia was a Christian priest living in Rome during the 3rd century. He is remembered for his devotion to Pope Callixtus I, whose remains he retrieved after they were discarded in a well around 222 AD. Following his attempt to provide a proper burial for the pope, Asterius was apprehended by the prefect Alexander. He was subsequently executed by being cast from a bridge into the Tiber River, after which his body was found at Ostia.