If I remember my old books correctly, they were not slaves, they were peasants who were paying tax as labour instead of money or produce. Like conscription, bu

If I remember my old books correctly, they were not slaves, they were peasants who were paying tax as labour instead of money or produce. Like conscription, but for civilian work. So there is still compulsion here, and the workers would often have had similar emotions and incentives as slaves. The fact that the workers had more freedom probably gave them more ability to act on that than if they had been proper slaves.