In his 2003 article “Conversion to Judaism in Classical Antiquity,” published in Hebrew Union College Annual, the classicist Louis Feldman analyzed the striking increase in the number of Jews between 586 BCE and the 1st century CE. He concluded that this was likely due to widespread, voluntary conversion to Judaism. In searching for clues as to the reasons behind this apparent trend, Pinchas Landis examines the legends of famous converts from antiquity, in both the Talmud and historical sources.
At the beginning of the first Jewish-Roman War in 66 CE, Nero Claudius Caesar Augustus Germanicus, known simply as Nero, was the emperor of Rome. It was he who sent Vespasian to put down the Jewish Revolt—the same Vespasian who, together with his son Titus, eventually conquered the country and destroyed the Second Temple.
Roman history records that, in 68 CE, a rebellion was mounted against Nero in Rome. He was declared a public enemy and sentenced to death by the Roman Senate in absentia. When Nero learned of his fate, he committed suicide.
Jewish [sources] tell a different story. The Talmud teaches that Nero came to Jerusalem during the war. In an attempt to see if fate would be on his side, he shot arrows in all four directions. All landed facing Jerusalem. In an attempt to explore further, he asked a Jewish child what verse in the Jewish Bible he was learning. The child responded by quoting the book of Ezekiel: “And I will lay My vengeance upon Edom by the hand of My people Israel.” [In talmudic literature, Edom is taken a stand-in for Rome.]
Nero concluded that “The Holy One, Blessed be He, wishes to destroy his Temple, and to wipe His hands with that man (referring to himself).” Nero then fled, and was so inspired by the pseudo-prophecy that he received that he converted to Judaism. The great Rabbi Meir, upon whose teaching much of the Mishnah is based, is said to be descended from him.
Read more on Aish.com: https://aish.com/the-surge-of-converts-to-judaism-in-ancient-rome/