Cults of Isis and Mithra were said to be popular among the ancient Hellenic people, despite being foreign deities. Even in Bactria Buddhist cult influenced many Greek people. Were the Hebrews or early Christians received similar treatment? Were there obscure cults of Yahweh practiced by Greek without actually converting to Judaism/Christianity?
A similar question was asked by u/New_Pakistani here with answers by me and u/throwawaydragon99999.
Both of us wrote practically the same, with me providing a case study on Salonica.