I was reading a book on economics, and the author claimed that the late Roman emperor Diocletian began the medieval era (in the sense of tying the serfs to the land). Diocletian faced many challenges as Roman emperor-his treasury was empty, inflation was raging, and his army was faced with having to defend the empire while severely understrength. His solution for the inflation was a comprehensive system of wage and price controls-which amounted to making tenant farmers into serfs. His price controls were widely evaded-and made the tax burden of supporting the army impossible.
So was Diocletian the first ruler of the medieval age?
It would be far more accurate to say that Diocletian laid the groundwork for Manorialism Manorialism - Wikipedia than that he ushered in Feudalism.
Feudalism tends to imply things like hereditary fiefdoms, which were more influenced by Germanic culture than Roman, and didn’t become the legal norm until long after Diocletian’s death.