Judaism
Note from Domitian by Suetonius

Titus had ordered that the Jewish Sanctuary Tax, due from every Jew throughout the world for Temple expenses (Exodus, xxx. 13; Matthew, xvii. 25), should be collected even though the Temple had been destroyed; and that Jews who paid were thereby permitted to practise their religion. However, a great many Greek converts to the Jewish ethical system, the so-called 'God-fearers', had declined to undergo circumcision (which would have made them technically 'Children of Abraham'), and were therefore not subject to the tax, though they kept the Sabbath and worshipped Jehovah as the One God. Suetonius probably refers to these rather than the Christians, who rejected the Sabbath and did all they could to prove they were not Jews.