From the third century AD onward, the city of Rome began an inexorable loss of authority as the central axis of the Empire, since the provinces were acquiring ever greater autonomy — something that had its origin in the sheer size of the Empire itself, vast and difficult to govern.

This situation led to the paralysis of many commercial activities, as well as to a halt in the conquests. The first meant that many cities could no longer collect taxes on commercial activity; the second, that with no further conquests one of the principal sources of revenue of the Roman state disappeared.

In the midst of this situation, many proprietors began to free their slaves, granting them a piece of land together with what was needed to work it — for which they paid through heavy tributes to the owner of the land, who thereby set himself up as a petty sovereign, holding control over vast tracts of territory.

It was in this condition of quasi-slavery that those subjected to the institution of the colonate found themselves. As is generally maintained, it made its appearance in the period of the Late Empire, since previously, in the classical period, the word colonus was used exclusively to designate either the proprietor who cultivated the soil of Rome or of the colonies, or else the tenant of another’s estate or land.

But in the Late Empire, doubtless as a consequence of Roman misery and weakness, the word colonus came to encompass the natural or physical person who remained bound in perpetuity to another’s land in order to cultivate it in exchange for a rent in money or in kind. Hence the claim that the colonus was a human individual of mixed condition, between slavery and freedom.

One became a colonus by birth, when the parents — or the mother alone — held that status, since the matter was hereditary; or by convention, that is, by agreement of wills; or by prescription of thirty years.

Coloni became entirely free by manumission, by promotion to the episcopate, and when they had lived as free men for a span of thirty years. Coloni were, in reality, slaves of the land — that is, servi terrae — because they could not abandon it at will, nor could they be separated from it without their consent. They were obliged, to be sure, to cultivate the ground and to pay the proprietor a rent in money or in kind, which did not make them the slaves of that proprietor; and so they were able to hold property of their own, to bind themselves by obligation and to marry. But in order to alienate the goods they might come to acquire, the consent of the owner of the land held in colonate had to intervene.

The owner of the land held the right of patronage — that is, the power the patron exercised over the colonus, who was bound to work the patron’s land in perpetuity and, should that land be sold, to submit to the authority of the new proprietor.