After the fall of western roman empire what filled the void left by the disintegration of political structure?

The people needed more coins to buy the same amount of food as before.

Feudalism

Explanation:

When the Roman Empire fell in 476 CE it began the period we know as the Middle Ages. The Roman Empire fell because of the series of attacks by the Barbarians, when the Roman Empire fell, people felt they were in danger because they did not have the Empire to protect them from the invasions.

Because of that, the feudalism system developed. In this system, the common people - such as peasants, serfs, and others - looking for protection, pledged loyalty to a lord, that was a landholder, in return, this lord would protect these people. The Lord remained powerful because the social classes were stable, people could not rise in the social status, which made possible for the lord to gain money from the serf's works.

the confederate at bull run