I. Christianity – II. Islam
1. Southern Arabia.
It is impossible to tell when the gospel was first preached in southern Arabia; probably Arabs from the region came into contact with Christianity in the course of their commercial travels or else Christians arrived in southern Arabia. Jewish and Christian missionaries probably paved the way for Southern Arabian monotheism, attested in inscriptions dating from 378 ce onward, which replaced the cult of astral deities with a single God. Around 342, the emperor Cons…