Flocculencio
Donor
If the Christian population of India OTL was descended from high-caste and Jewish families who were converted by St. Thomas, and the caste system works to prevent evalgelizing by the original converts, why not make the POD that St. Thomas converts different people?
This is a good point but this gives you a higher risk of Thomas being killed as a troublemaker. IOTL he travelled all over S. India but what happens if he lands at Cochin, starts preaching to the untouchables and pissess off the local elites? They have him killed and he never gets to do the extended missionary journey he did IOTL.