The Roman Empire was a superstate which, at the height of its power, encompassed territory extending over much of what is now Western Europe, North Africa and Asia Minor. It was governed from Rome for almost 500 years but eventually collapsed at the end of the fourth century. Historians offer many explanations to account for this decline, citing a failing economy, military weakness, the rise of Christianity, natural disasters and even climate change as contributing factors. One of the most widely accepted theories attributes the downfall of Rome to a complacency that led to a series of invasions by barbarian tribes. As the imperial army had become too underfunded to maintain the borders of its enormous empire, soldiers were powerless to prevent the migration and settlement of entire tribal populations into Roman territory.

This influx of outsiders eventually transformed the political structure of Western Europe. They were hostile to Roman rule, and the centralized governing body fragmented as local rulers began to emerge from the ranks of the tribal groups.

As the invading tribesmen took up important leadership positions, their status as non-Romans eventually diminished: tribal leaders married into aristocratic Roman families, and they began to exercise influence over political decisions. As the two cultures combined over a number of generations, however, they did not resolve the financial problems plaguing the empire. The new tribal leaders refused to pay taxes, which further deprived the military of necessary funding. Instead of being paid in money, soldiers were given land or had their rents forgiven; consequently, they too paid no tax, and the system deteriorated further and further.