Explain the reasons for the military successes of the Arabs.

Prophet Muhammad managed to unite the Arab tribes to his death by capturing the Arabian Peninsula. The Arabs willingly went to war, because the Koran allowed wars in the name of spreading Islam – Jihad. Two powerful neighbors, the Byzantine and Sassanian empires, at first glance, were much stronger and more powerful than the newly-made caliphate. But these powers have long competed with each other, and because of many wars weakened, which allowed the Arabs to easily grab a piece of territory. There were no uprisings in the caliphate, since many infidels easily accepted Islam. Therefore, the Arabs continued their expansion freely.