Under Darius’ rule, the Achaemenid Empire, the largest empire of its time, depended on a balance between central initiative and local administration. Divided into twenty three satrapies spread over thousands of miles, Achaemenid rulers needed methods to discourage local groups from becoming independent and seceding from the empire. Military forces and tax collectors were used to check the power and independence of the satraps who governed each territory. Spies, “the eyes and ears of the king,” were also dispersed throughout the empire to gather and report information. These methods helped Achaemenid rulers keep the empire under control and unified. Lastly, Cyrus and Darius, but not Xerxes, valued the culture and beliefs of the people they ruled. This reduced the chances of people rebelling because they are forced to live following a certain religion. The government also worked on building roads to facilitate trade and communication. The Han dynasty of China primarily used a centralized government. The empire was administered by an enormous bureaucracy, which needed a steady supply of educated candidates. The Imperial University was established to educate students so they will be prepared to government service. Roads were also built during the Han dynasty to assist trade and communication. Both the Achaemenid Empire and the Han dynasty had vast empires to control. While the Achaemenid Empire divided its land with governors for each area, the Han dynasty depended on a bureaucracy to maintain control. The Achaemenid Empire relied on military forces, tax collectors, and spies to maintain the effectiveness of their system of satapies. The Han dynasty relied on a continuous supply of educated officials to become part of its bureaucracy. Both dynasties built roads to help with expansion and to help regulate and expedite trade and communication.