Note 8 — Chapter III · THE SPREAD OF ISLAM AMONG THE CHRISTIAN NATIONS OF WESTERN ASIA.

That force was not the determining factor in these conversions may be judged from the amicable relations that existed between the Christian and the Muslim Arabs. Muḥammad himself had entered into treaty with several Christian tribes, promising them his protection and guaranteeing them the free exercise of their religion and to their clergy undisturbed enjoyment of their old rights and authority.8 A similar bond of friendship united his followers with their fellow-countrymen of the older faith, many of whom voluntarily came forward to assist the Muslims in their military expeditions in the same spirit of loyalty to the new government as had caused them to hold aloof from the great apostasy that raised the standard of revolt throughout Arabia immediately after the death of the Prophet.9 It has been suggested that the Christian Arabs who guarded the frontier of the Byzantine empire bordering on the desert threw in their lot with the invading Muslim army, when Heraclius refused any longer to pay them their accustomed subsidy for military service as wardens of the marches.10