For the developments of the Middle Ages See Serfdom and Villenage.
The great beauty and fertility of the country, as well as the charm of its climate, undoubtedly attracted, even in early ages, successive swarms of invaders from the north, who sometimes drove out the previous occupants of the most favored districts, at others reduced them to a state of serfdom, or settled down in the midst of them, until the two races gradually coalesced.
The lay subjects of the Order consisted of two classes; on the one hand there were the conquered Prussians, in a position of serfdom, bound in time of war to serve with the brethren in foreign expeditions; on the other hand there were the German immigrants, both urban and rural, along with the free Prussians who had voluntarily submitted and remained faithful.
The influence of the Northern invasions on the change from slavery to serfdom was, in all probability, of little account.
Not very long after the disappearance of serfdom in the most advanced communities comes into sight the new system of colonial slavery, which, instead of being the spontaneous outgrowth of social necessities and subserving a temporary need of human development, was politically as well as morally a monstrous aberration.