Foreign religions grew rapidly in the 1st-century A.D. Roman Empire, including worship of Jesus Christ, the Egyptian goddess Isis, and an eastern sun god, Mithras. Of the religions that expanded rapidly in the 1st-century Roman Empire, worship of Mithras was particularly popular among Roman soldiers, who spread his cult during their far-flung travels... Mithras's temples, called Mithraea, are the best archaeological evidence of the god's worship, and most of them featured a characteristic depiction of Mithras slaying a bull, a scene called the tauroctony... In the later Roman Empire, Mithras blended in with another sun god, Sol Invictus, the "unconquered...