Empires as systems

Empires have a central group that controls outside groups. The outside groups were on the periphery and had fewer rights. A third group could also affect an empire. These were the people living just outside its border. They were tribal groups and were sometimes nomads or semi-nomadic. Empires often saw these people as barbarians. Sometimes an empire bordered another powerful state.

Empires were also networks where goods could be traded. People outside the border could take part as well. Merchants often crossed borders. There were also exchanges of ideas. Barbarian groups usually adopted some characteristics of the empire.

Why do empires collapse?

Historians debate about how empires collapse. There are many theories. There are usually patterns within empires that collapse. Two measures, in particular, show the health of an empire.

The first is money. Empires are expensive to maintain. Healthy empires could respond to invasion and disasters. An empire low on money and resources could not.

The second measure is cohesion, which means unity. People at the center of an empire could lose a feeling of connection to it. Groups on the outside could develop unity with each other.

Another factor is the change in population. If it went down, there were not enough people to pay taxes. If the population went up, there were not enough resources for everyone.

From theory to reality: Han dynasty China and the Roman Empire

The Western Roman Empire fell in 476 CE. The Han dynasty in China fell in 220 CE. These were powerful empires. They collapsed due to similar reasons.

Both had money problems. Elites in both empires used tax money for their own use. Roman peasants evaded tax collectors. People in the Han dynasty fled the barbarian attacks. This snowballed into a bigger problem. The empire was unable to collect tax money from the people who fled. But the empire needed that money to fight off the barbarian raids.

Both empires also had problems with unity. Both treated the outside groups poorly. These groups came together and became threats to the empire.

Collapse elsewhere

There are many examples from around the world of empires collapsing. The Persian Empire weakened through civil war. It was not strong enough to resist Alexander the Great.

The Inca empire fell to the Spanish in the 1500s. It was not because the Europeans were superior. It was not because the Incas were less developed. It was because there had been a long civil war in the Incan empire. Anti-Incan groups caused trouble out on the periphery. The elites stopped supporting the empire. The Spanish arrived at a bad time for the Incan Empire.