The Byzantine empire established a system of government very different than that of the Roman Empire (I will not discuss the Barracks Emperors because they were essentially part of the internal decay or the Roman Empire). The Roman Republic created a republican constitution that specified the power that was invested in each of the two counsels who had control over the military and civil affairs. Counselors were elected from the aristocratic and wealthy families (patricians) and served one year terms (tribunes were later established who represented interests of the plebs). Now the Roman Republic later became the Roman Empire through Caesar who established himself as a never ending dictator (used to only rule in times of strife). Caesar was quickly disposed of though and Augustus took over and established a Monarchy (with loyal governors). Now the Byzantine Empire as states earlier was a highly centralized bureaucracy and would later establish the themes system which established generals as civic administration in a given region who incorporated local, free peasants in private armies. This new system of government allowed Byzantine forces to quickly react to Islamic attacks, and generals can use this to expand the empire. Generals Like Basil II vastly increased its domains and accumulated vast wealth. Was established domination over the Mediterranean. Moreover it gave grants to the free peasantry who joined thus they gained land (increased agriculture production) like how private armies were built under local rulers in the Roman Empire (Caesar). Moreover incorporation of past Roman law such in documents such as Justinian's Code.