Parthian and Sassanian Satraps
In the Parthian Empire, the king's power rested on the support of noble families who ruled large estates, and supplied soldiers and tribute to the king. City-states within the empire enjoyed a degree of self-government, and paid tribute to the king. Administration of the Sassanid Empire was considerably more centralized than that of the Parthian Empire; the semi-independent kingdoms and self-governing city states of the Parthian Empire was replaced with a system of "royal cities" which served as the seats of centrally appointed governors called shahrabs as well as the location of military garrisons. Shahrabs ruled both the city and the surrounding rural districts. Exceptionally, the East Roman Empire also adopted the title "satrap" for the semi-autonomous princes that governed one of its Armenian provinces, the Satrapiae.
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