Without these two empires, much of the Greek knowledge known today would not have existed. These two empires brought back into popularity much of Greek culture and philosophy. There are many similarities that should be compared between the Byzantine Empire and the Islamic Caliphates.
The Islamic Caliphates adopted an administrative structure based on Byzantine models. Caliphs of the Abbasid dynasty in Baghdad were absolute monarchs. They assumed new names when they started ruling and claimed divine support for their authority. The decline began when local regimes took up power. In the Byzantine state, the emperor became the sole and absolute ruler. The Senate ceased to have real political and legislative authority but remained as an honorary council with titular members. These are two very similar forms of government. This similarity could be due to necessity. Large societies usually have some form of an absolute monarch. These monarchs can be seen in Justinian I of the Byzantine Empire and Harun-al Rashid of the Abbasid Caliphate. Under both of these rulers, their respective empires began to decline.
Because of the rule of Harun-al Rashid, major uprisings began due to his attempts at controlling the local rulers, and civil war broke out. This divided and weakened the Abbasid caliphate. The decisions that led to these massive problems seemed not to be bad or unwise, they seemed too assuming. Trying to control the local rulers presumed their loyalty in him and splitting the empire between his two sons presumed they could get along and not become power-hungry. Justinian shared the same ambition. He tried to extend his empire back to its former glory. He stretched out the empire too far. Justinian did not protect the capital and that caused the downfall of the empire. These were two very famous leaders that both inadvertently caused the fall of their empires.
Byzantine trade was controlled by the state. The state strictly controlled both local and external trade and issued money that reacted well to the trading needs of the economy. The Islamic Caliphates, on the other hand, encouraged capitalism to promote tax revenues. Many forms of banking and currency were developed during this time. Byzantine took after its predecessor of Rome in its strict policies. This influence impacted how the economy of Byzantine developed. From an agricultural aspect, large-landed estates still existed and flourished. The demand for large amounts of cheap produce was still there as well as the desire for much money off the produce. The Islamic Caliphates sought a different route to making money. The government allowed the little farmers flourish and make a living for themselves. There needed to be strong incentive to increase the productivity and wealth of these farmers that allowed the government greater tax revenues.
New farming techniques as well as crops were diffused among different parts of the world through trade routes. These new crops and techniques along...