The power of the father or chief of the household—patria potestas—was limitless, in the precincts of the house, over both the family and the servants. The father, be he patrician or plebeian, could sell his son into slavery, but the right was very seldom used. So also, the father had the right of life and death over all his family and household. Manumission of slaves was common; it existed from the most ancient times. The slave could also buy his liberty. Subsequently, in the last centuries of the republic and under the emperors, a slave could be emancipated by various positive enactments, and the status of the manumitted slave often passed through various gradations before reaching absolute independence. The fortieth book of the Pandects contains several chapters relating to manumission.

Sometimes, though rarely, under the kings, the public slaves—or those of the state, exclusively war prisoners—were employed on public works, or to take care of public buildings, or to attend on magistrates or priests. The condition of public slaves was preferable to that of the private slaves; indeed, the former subsequently had the right to dispose by will of half of their property.

The land was tilled by the hands of the senators themselves, patricians though they were. If a patrician (pater) possessed more land than he could cultivate himself, he divided it among small free cultivators, or let it out; and no servile hand desecrated the plough. The slaves employed in the house were not numerous.

King Servius Tullius inaugurated a political reform, intended to alleviate the condition of the plebeians oppressed by the patricians; and in preparation for it he took a census. At that time Rome had eighty-four thousand able-bodied citizens between the ages of eighteen and sixty years, or a total population of about four hundred thousand free persons of all ages and sexes. To this number must be added the plebeians, who were not yet citizens. The artisans, operatives, clients and strangers perhaps doubled this estimate of the population of Rome, the limits of which then stretched from the Tiber to the Anio, including, probably, the lands of Alba, and making in all, an area of about one hundred and twenty or one hundred and forty square miles. There would thus be more than five thousand five hundred inhabitants to a square mile; so that there could have remained but very little room for slaves.

In the first stages of the republic, the patricians continually increased their landed estates, and by renting these to tenants, they acquired power over the poor free laborers, and by lending them money, got a claim on their bodies and also on the free yeomen and rustics. The patricians were hard creditors, and rigorously availed themselves of their legal rights, and their ergastula—caves or vaulted prisons—were almost continually filled with poor debtors. This impoverishment of the free yeomanry increased after the terrible devastations perpetrated by the Gauls under Brennus. Finally, these financial oppressions generated those revolts of the plebeians which terminated in their obtaining political rights and full citizenship, together with the jurisprudential reform known as the Twelve Tables.

During the first three or four centuries of the republic, the number of slaves who were non-debtors was very limited. At the census made in the year of Rome 280, the free population amounted to over four hundred and ten thousand persons, and there were then only seventeen thousand slaves.

Few, if any, women were originally enslaved. If the nursling of a Roman family often drew its milk from the paps of a slave woman, the Roman matron, in turn, often gave her breast to the babe of a slave.

In those early times the slaves were kindly treated; they were regarded rather as members of the family than as chattels; they took their meals with their masters, and participated in the sacrifices and worship of the gods. They were not considered dangerous elements in the household or the state. From that early epoch also date certain privileges conceded to the slaves—such as their earnings or peculium, which, at first established only by common usage, became afterward defined and specified by the civil law, in which originally the slave was almost entirely ignored.

Plebeians, proletarians, clients, free artisans—almost all of whom were Romans—formed, in the first centuries, the bulk of the slaves kept in the ergastula of the patricians. Frequently, when a consul wanted soldiers, he would order the creditors to open their vaults and disgorge the victims for his service in a campaign. And sometimes, though rarely, a consular edict quashed the debts and set them free.

In these earliest times of the Republic the name of a proletarius, or procreator of children, was held in honor. It was to an increase of the number of its freemen, not of its slaves, that the Republic hoped for duration and power. To be called colonus, or a cultivator, was also an honor to a Roman citizen, whether patrician or plebeian, in the times of Cincinnatus, Dentatus, and Regulus. Labor was then a high distinction, nay it was sacred; and a slave may almost be considered an accident in domestic pursuits. Scaurus, then one of the wealthiest and most powerful senators, had six slaves, Curius Dentatus one, Regulus one, when he commanded the Roman legions against Carthage, while Cincinnatus may have had one, but most probably none.