An early Christian reference was of Pomponia Graecina, the wife of Aulus Plautius who was accused of following a foreign superstition. She was tried by her husband in front of the family, as was the tradition of high ranking Romans, and found innocent.
This was in 57 AD.
The foreign superstition is surmised and supported by 3rd century inscriptions commemorating the gens Pomponius.
(Furneuax, Tacitus am. ad. loc.)
Henry Bettenson, Documents of the Christian Church, Oxford University Press, Oxford, 1963