Both the Byzantine Empire and the Chinese dynasties of the post-classical era were rich and powerful; but each faced unique problems. Each was ruled by a powerful Emperor, the Byzantine Emperor was head of both church and state; the Chinese Emperor ruled under the Mandate of Heaven. All governmental officials in both answered directly to the Emperor.
The Byzantine Empire with its capital at Constantinople was exceptionally rich and powerful for a number of years after the collapse of the Eastern Empire in 476 C.E. Constantinople was an opulent city modeled after ancient Rome with a Hippodrome for races, circuses, and other athletic events. Byzantine Emperors were at times ostentatious in displaying their wealth; in one instance an Emperor sat on a throne which could be moved up and down to demonstrate his power. Mechanical devices were installed to emulate birds singing and lions roaring and swishing their tails, again to impress visitors. So ostentatious was this display that the term "Byzantine" as an adjective applies to any operation that is convoluted and involves numerous steps to complete. For all its majesty, Byzantium was unable to control its land holdings. Although the Emperor Justinian managed to regain much of the old Roman Empire, his success was short lived. After his death, Islamic forces defeated Byzantine forces at the Battle of Mazinkert, and soon occupied much of Anatolia (present day Turkey.) It was in response to the Islamic threat that the Byzantine Emperor wrote to Pope Urban II asking for assistance which in turn led to the launch of the First Crusade. There was only one notable revolt in Byzantium, this during the reign of Justinian. The revolt was the result of high taxes and destroyed the city but did not bring down the Emperor. Rather than crush the peasants, Justinian rebuilt the city to make it more magnificent than before. His projects included the famous Hagia Sophia, the Church of Holy Wisdom.
At the same time, China was controlled by the Sui and Tang dynasties. They engaged in a number of expensive work projects, including the construction of the Grand Canal, which stretched over 1200 miles. This and other public works were expensive, however and were built with forced labor and paid for by expensive taxes on the peasantry who soon revolted. The end result was the assassination of the Sui Emperor, Sui Yangdi and the end of his dynasty. They were followed by the Tang dynasty, which lasted over 300 years. This dynasty provided for equal land distribution under an "open field" system whereby land was distributed according to family needs and the land's fertility. One fifth of the land so distributed was inheritable. Bureaucratic positions were awarded according to a Confucian system of merit rather than inheritance or connections. Tang Emperors managed to extend their Empire as far as Vietnam to the South and the Aral sea to the North. An extensive system of roads and canals was so efficient that a large corps of runners could deliver fresh seafood to the Emperor over a distance of 600 miles in less than nine days. The Empire finally went into decline in 755 C.E. when an incompetent Emperor spent less time on ruling and more on his mistress and music.