Nobody has mentioned how serfdom first developed. During the later days of the Western Roman Empire, taxes were so high on the middle class (artisans, craftsmen, farmers) that they were literally selling themselves into slavery because slaves were not taxed. People were willing to trade their physical freedom for economic freedom. The middle class was taxed out of existence – only the poor and the tax-exempt aristocrats were remained.

To stop the loss of tax revenue, the Emperor decreed that free men could no longer sell themselves into slavery and farmers were no longer allowed to leave their farms. They were now medieval serfs.