Changes

This signaled the start of a 26-year war between the Empires. The Byzantine army was demoralized and leaderless, and they were soon defeated. Phocas rule was tyrannical, and law and order collapsed in many areas. The troops of Khosrau II occupied Syria, Palestine, Armenia and entered Egypt by 608 AD. Phocas was eventually deposed by Heraculus, who was to save the Empire ultimately. He defeated a siege of Byzantium and later launched a counter-attack that led to Khosrau II's defeat and the recapture of all the lost Byzantine provinces. However, the Orthodox Christian Empire was severely weakened and was only a shadow of what it had been in 600 AD, and this was important repercussions for the future of Europe and the Middle East. If Maurice had lived and passed the throne to one of his sons, the mutually ruinous conflict between Byzantine and Sassanian could have been avoided.

The Prophet Muhammad unified the disparate and feuding Arab tribes and transformed them into a formidable fighting force. In 629, the Prophet called for a Jihad against the Byzantine and Persian Empires. Emperor Heraclius had not been able to consolidate Byzantine power in the areas that Khorsau II had occupied. At the battle of Yarmouk, the army of the Christian Empire was decisively defeated by the Muslims. This led to the loss of Palestine, including the Holy City of Jerusalem and Syria. By 642 AD, Egypt was also conquered by the Arab armies, who by 660 had captured North Africa. The collapse of Byzantine power in these areas was remarkably swift. This resulted from the brutal conflict between the Persians and the Byzantines that had broken out after the fall of Maurice.

The Arab conquests were facilitated by the usurpation of Phocas and his disastrous reign. If Maurice had lived, the Byzantine’s would have been in a better position to withstand the Arab onslaught.<ref> Kennedy, H., The Prophet and the age of the Caliphates: The Islamic Near East from the sixth to the eleventh century (London, Routledge, 2015), p 178</ref> This could have ensured that Syria, Palestine, and North Africa would have remained part of the Empire and part of the Christian World. Instead, these areas came under Arab control and eventually became largely Muslim.

====The Slavs in the Balkans====

The Balkans army had to be moved to the east to counter the growing Persian threat after Maurice’s brutal execution. The Persian invasions forced Emperor Heraclius to concentrate all his forces in Anatolia. This led to the collapse of the Byzantine Balkan frontier, and the Avars raided the walls of Byzantium and even took part in the Persian siege of the city in 626 AD. The Slavic tribes who had been largely pushed back beyond the Danube by Maurice were once again able to enter the Balkans. The Avars remained by and large beyond the Danube. These tribes settled in agricultural areas and formed petty kingdoms.<ref> Curta, Florin Southeastern Europe in the Middle Ages, 500–1250. Cambridge: Cambridge University Press, 2006), p 134</ref>