The Persian Empire was built on an intricate kingship cult, in which the monarch, ensconced in regal splendor, could only be addressed through an elaborate ceremony.
The empire was sustained by more than conquest and imperial order. Persian governors, known as satraps (SAY-traps), were placed in each of the empire's twenty-three provinces, while lower-level officials were recruited from local authorities.
A system of uniform coinage, predictable taxes placed on each province, and a freshly excavated canal linking the Nile and the Red Sea considerably boosted commerce and enriched Egypt were all part of the empire's infrastructure.
The Persian Empire's tremendous riches and power were reflected in elaborate imperial cities, particularly Susa and Persepolis. These towns were significant emblems of imperial authority thanks to palaces, audience halls, harem quarters, monuments, and carvings.
The Greeks, who called themselves Hellenes, built a civilization that was distinct in many aspects, especially when compared to the Persians. Greece and the Aegean basin had a population of only 2 million to 3 million people, a fraction of the Persian Empires.
Although each of these city-states was fiercely independent and frequently at odds with its neighbors, they shared a lot in common, such as speaking the same language and worshipping the same gods.
The Greeks were an expansive nation, like the Persians, but their expansion took the form of settlement in far-flung locations rather than conquest and empire. An increasing population is pushing people to do things they don't want to do.
The amount of popular participation in political life that happened within at least some of the city-states was the most distinguishing trait of Greek civilization and the largest contrast with Persia. It was the concept of "citizenship," of free people managing the business of the state, of equality before the law for all citizens, that was so distinctive.
Alexander died in 323 b.c.e. without returning to Greece, and his empire was quickly divided into three kingdoms, each headed by a group of powerful Macedonian generals.
The various cities that Alexander and other Hellenistic rulers created throughout the empire were a vital conduit for the transmission of Greek culture. These cities, which were adorned with Greek monuments, sculptures, theaters, markets, councils, and assemblies, drew tens of thousands of Greek settlers who worked as state officials, warriors, or commerce.
Cities like Alexandria stood out from the rest of Greece's ancient city-states, both in terms of cultural diversity and the lack of independence prized by Athens and Sparta.
However, the cultural divide between Greeks and natives was far from complete, and there was a good amount of cultural exchange and mingling. Alexander had married several Persian princesses and actively encouraged marriages among his army with Asian women.
By the first century b.c.e., the Hellenistic kingdoms that had sponsored it had deteriorated and disappeared, and most of this Greek cultural impact had faded. It was, however, a spectacular cultural encounter created by the collision of two empires and two second-wave civilizations for the time it lasted.
Empires rise and fall with seeming regularity, posing one of history's most vexing questions: what causes these once-mighty institutions to crumble? The Han dynasty empire in China came to an end around 220 c.e., whereas the Roman Empire's final disintegration is traditionally dated to 476 c.e., despite a long period of decline.
Despite their variations, the demise of these imperial powers has been linked to a number of similar reasons. At one level, they had simply grown too huge, too overextended, and too costly to be supported by the current resources, and there was no major technical advance available to expand these resources.
Rivalry among elite groups weakened imperial authority and caused instability in both empires. The state in China was weakened by the ongoing conflict between castrated court officials (eunuchs) loyal to the emperor and Confucian-educated scholar-bureaucrats. Between 235 and 284 c.e., twenty-six people claimed the title of Roman emperor, although only one of them died of natural causes.
Historians have frequently connected the fall of empires to environmental conditions, more so in the case of Rome than in the case of Han dynasty China. Drought in the third century, cold and rainy weather in the fourth, and greater rainfall and colder temperatures in the fifth century, all of which resulted in significant soil erosion.