Onkelos — known in some traditions as Aquila — was a Roman nobleman, a nephew of the Emperor himself, who converted to Judaism. His conversion scandalized the imperial court and became one of the most famous stories of religious transformation in the ancient world.
The Talmud (Avodah Zarah 11a, Gittin 56b) records that before converting, Onkelos consulted the spirits of three deceased men to ask their advice about joining the Jewish people. He summoned Titus, the destroyer of the Temple, who told him the Jews were too burdensome. He summoned Balaam, who told him not to seek their welfare. Each spirit, speaking from its experience of opposing Israel, warned him away.
But Onkelos was not deterred. He saw in the Jewish people something that their enemies could not see — a relationship with God so deep that even destruction could not sever it. He converted.
The Emperor sent soldiers to arrest him. Onkelos engaged each group in conversation about Torah, and each group was so moved that they converted as well. The Emperor sent a final group with strict orders: "Do not speak to him at all." But as they were dragging him away, Onkelos touched the mezuzah (a parchment scroll affixed to doorposts) on his doorpost and smiled. "What is that?" the soldiers asked, unable to resist. "In the world," Onkelos explained, "a king sits inside his palace while his servants guard him from outside. But God — His servants sit inside their homes, and He guards them from outside." The soldiers converted.
Onkelos went on to produce the authoritative Aramaic translation of the Torah — the Targum Onkelos — which is studied to this day. The Roman nobleman became one of the pillars of Jewish scripture.