Christianity.
The principal tribes that embraced Christianity were Ghassan, Taghlib, Tai’ and some Himyarite kings  as  well as other tribes living on the borders of the Roman Empire.
Magianism was also popular among the Arabs living in the neighbourhood of Persia, Iraq, Bahrain, Al-
Ahsâ’ and some areas on the Arabian Gulf coast. Some Yemenis are also reported to have professed
Magianism during the Persian occupation.
As for Sabianism, excavations in Iraq revealed that it had been popular amongst Kaldanian folks, the
Syrians and Yemenis. With the advent of Judaism and Christianity, however, Sabianism began to give  way to the new religions, although it retained some followers mixed or adjacent to the Magians in Iraq  and the Arabian Gulf.
THE RELIGIOUS SITUATION:
Such was the religious life of the Arabians before the advent of Islam. The role that the religions  prevalent played was so marginal, in fact it was next to nothing. The polytheists, who faked
Abrahamism, were so far detached from its precepts, and totally oblivious of its immanent good  manners. They plunged into disobedience and ungodliness, and developed certain peculiar religious  superstitions that managed to leave a serious impact on the religious and socio-political life in the  whole of Arabia.
Judaism turned into abominable hypocrisy in league with hegemony. Rabbis turned into lords to the  exclusion of the Lord. They got involved in the practice of dictatorial subjection of people and calling  their subordinates to account for the least word or idea. Their sole target turned into acquisition of  wealth and power even if it were at the risk of losing their religion, or the emergence of atheism and  disbelief.
Christianity likewise opened its doors wide to polytheism, and got too difficult to comprehend as a  heavenly religion. As a religious practice, it developed a sort of peculiar medley of man and God. It  exercised no bearing whatsoever on the souls of the Arabs who professed it simply because it was  alien  to their style of life and did not have the least relationship with their practical life.
People of other religions were similar to the polytheists with respect to their inclinations, dogmas,  customs and traditions