Bahrain (historical Region)
By the fifth century the Bet Qatraye was a major centre for Nestorian Christianity (which had come to dominate the southern shores of the Persian Gulf), with Samahij being the seat of bishops. It was a center of Nestorian Christianity until al-Bahrain adopted Islam in 629 AD. As a sect, the Nestorians were often persecuted as heretics by the Byzantine Empire, but Bahrain was outside the Empire's control offering some safety. The names of several of Muharraq Island’s villages today reflect this Christian legacy, with Al Dair meaning “the monastery” or "the parish."
In 410, according to the Oriental Syriac Church synodal records, a bishop named Batai was excommunicated from the church in Bahrain.
Read more about this topic: Christians In The Persian Gulf