In Roman law (today as well as in Roman times), both land and movable property could be owned absolutely by individuals. This conception of absolute ownership (dominium) is characteristically Roman, as opposed to the relative idea of ownership as the better right to possession that underlies the Germanic systems and English law.

Mancipatio, or formal transfer of property, involved a ceremonial conveyance needing for its accomplishment the presence of the transferor and transferee, five witnesses (adult male Roman citizens), a pair of scales, a man to hold them, and an ingot of copper or bronze. The transferee grasped the object being transferred and said, “I assert that this thing is mine by Quiritarian [Roman] law; and let it have been bought by me with this piece of copper and these copper scales.” He then struck the scales with the ingot, which he handed to the transferor “by way of price.”

In jure cessio was a conveyance in the form of a lawsuit. The transferee claimed before the magistrate that the thing was his, and the transferor, who was the defendant, admitted the claim. The magistrate then adjudged the thing to the transferee. (The sham-lawsuit theory, however, is not acceptable to all modern scholars, principally because the judgment of ownership was valid against any possible private claimant, not merely against the defendant, as in a true lawsuit.)

Usucapio referred to ownership acquired by length of possession. In early Roman law, two years of continuous possession established title in the case of land, one year in the case of movables. In the developed law, possession must have begun justifiably in good faith, and the thing must not have been stolen (even though the possessor himself may have been innocent of the theft) or acquired by violence.

In terms of occupatio, ownerless things that were susceptible to private ownership (excluding such things as temples) became the property of the first person to take possession of them. This applied to things such as wild animals and islands arising in the sea. In some views, it also applied to abandoned articles.

Accessio worked in this manner: if an accessory thing belonging to A was joined to a principal one belonging to B, the ownership in the whole went to B. For example, if A’s purple were used to dye B’s cloth, the dyed cloth belonged wholly to B. By far the most important application of this rule asserted that whatever is built on land becomes part of the land and cannot be separately owned.

Specificatio was somewhat different. If A made a thing out of material belonging to B, one school of thought held that ownership went to A, and another held that it remained with B. Justinian adopted a “middle opinion”: B retained ownership if reconversion to the original condition was possible (a bronze vase could be melted down); A obtained ownership if it was not (wine cannot be reconverted into grapes).

According to thesauri inventio, or treasure trove, the final rule was that if something was found by a man on his own land, it went to him; if it was found on the land of another, half went to the finder, half to the landowner.

Traditio was the simple delivery of possession with the intention of passing ownership and was the method of conveyance of the jus gentium. If A sold and merely delivered a slave to B, under the jus civile, A remained the owner of the slave until a specified length of time had elapsed. The praetors, however, devised procedural methods of protecting B’s possession in such a way that A’s title became valueless, and B was said to own the thing in bonis. This was a remarkable triumph for informality in the granting of title. From the phrase in bonis, later writers coined the expression “bonitary ownership.” Justinian abolished the theoretical distinction between civil and bonitary ownership.

The ordinary leaseholder had no protection beyond a contractual right against a landlord and could not assign tenancy. But there were certain kinds of tenure that did provide the tenant protection and that were assignable: agricultural and building leases granted for a long term or in perpetuity often enabled leaseholders to enjoy rights hardly distinguishable from ownership.

There were also servitudes, in which one person enjoyed certain rights in property owned by another. Rights of way and water rights were rustic servitudes; rights to light or to view were urban servitudes. Ususfructus was the right to use and take the fruits (such as crops) of a thing and corresponded to the modern notion of life interest. A more restricted right, likewise not extending beyond the life of the holder, usus permitted merely the use of a thing; thus, a person could live in a house but could not let it, as that would be equivalent to “taking the fruits.”

Since ownership was absolute, it was sharply distinguished from possession, which the civil law did not protect as such. Any owner wishing to interfere with an existing possessor, however, had to bring legal action to prove his title. If he interfered on his own authority, the praetor would see that the original state of affairs was restored before adjudicating the title.

Delict and contract

Obligations were classified by classical jurists into two main categories, according to whether they arose from delict or contract. Justinian’s law recognized two further classes of obligation, termed quasi-delict and quasi-contract.

As early as the 6th and 5th centuries bce, Roman law was experiencing a transition from a system of private vengeance to one in which the state insisted that the person wronged accept compensation instead of vengeance. Thus, in the case of assault (injuria), if one man broke another’s limb, talio was still permitted (that is, the person wronged could inflict the same injury as he had received); but in other cases, fixed monetary penalties were set. Theft involved a penalty of twice the value of the thing stolen, unless the thief was caught in the act, in which case he was flogged and “adjudged” to the person wronged.

By the early empire, reforms had substituted a fourfold penalty in the case of a thief who was caught in the act, and the court assessed all penalties for injuria (which by then included defamation and insulting behaviour). The law of damage to property was regulated by statute (the Lex Aquilia), which in turn was much extended by interpretation. Additionally, there were situations in which a person could be held liable for damages even though he was not personally responsible. In Justinian’s Institutes only four delicts were dealt with: theft, robbery with violence, damage to property, and verbal or physical assault.

In the early republic, a law of contract hardly existed. There was, however, an institution called nexum, of which little can be said with certainty except that it was a kind of loan so oppressive in character that it could result in the debtor’s complete subjection to the creditor. It was obsolete long before imperial times. The contracts of classical law were divided into four classes: literal, verbal, real, and consensual. The literal contract was a type of fictitious loan formed by an entry in the creditor’s account book; it was comparatively unimportant and was obsolete by Justinian’s day. The verbal contract required set words or patterns of words to be spoken. The stipulatio was the most important form of verbal contract, for it established a form in which any agreement (provided it was lawful and possible) could be made binding by the simple method of reducing it to question and answer: “Do you promise to pay me 10,000 sesterces?” “I promise.” Originally it was absolutely necessary that the words be spoken, but by Justinian’s day a written memorandum of such a contract would be binding, even though, in fact, nothing at all had been spoken.

If an agreement was not clothed in the form of a stipulation, it must, to be valid, fall under one of the types of real or consensual contracts. A real contract was one requiring that something should be transferred from one party to the other and that the obligation arising should be for the return of that thing. Real contracts included loans of money, loans of goods, deposits, and pledges. Consensual contracts needed nothing except verbal or written agreement between the parties, and though there were only four such contracts known to the law, they were the most important in ordinary life—sale, hire of things or services, partnership, and mandate (acting upon instructions). In Justinian’s day there was a further principle that in any case of reciprocal agreement, such as an agreement for exchange (but not sale), if one party had performed, he could bring an action to enforce performance by the other. In addition to the foregoing contracts, a few other specific agreements were recognized as enforceable, but the general recognition of all serious agreements as binding was never achieved by the Romans.

Quasi-delict covered four types of harm, grouped together by no clearly ascertainable principle. They included the action against an occupier for harm done by things thrown or poured from his house into a public place and the action against a shipowner, innkeeper, or stablekeeper for loss caused to customers on the premises through theft or damage by persons in his service.

Quasi-contract embraced obligations that had no common feature save that they did not properly fall under contract, because there was no agreement, or under delict, because there was no wrongful act. The most noticeable examples were, first, negotiorum gestio, which enabled one who intervened without authority in another’s affairs for the latter’s benefit to claim reimbursement and indemnity, and second, the group of cases in which an action (condictio) was allowed for the recovery by A from B of what would otherwise be an unjustified enrichment of B at A’s expense, such as when A had mistakenly paid B something that was not due (condictio indebiti). This notion of unjust enrichment as a source of legal obligation was one of the most pregnant contributions made by Roman law to legal thought.

The law of succession

The law of succession is one of the most complex areas of Roman law. Any Roman citizen who was of age could make a will, but several very formal requirements had to be met for the will to be valid. The first requirement was the appointment of one or more heirs. An heir, in the Roman sense of the term, was a universal successor; that is, he took over the rights and duties of the deceased (insofar as they were transmissible at all) as a whole. On acceptance, the heir became owner if the deceased was owner, creditor if he was creditor, and debtor if he was debtor, even though the assets were insufficient to pay the debts. It was thus possible for an inheritance to involve the heir in a loss. Until Justinian’s day this consequence could be avoided only by not accepting the inheritance, though certain categories of heirs could not refuse. Justinian made one of his most famous reforms by providing that an heir who made an inventory of the deceased’s assets need not pay out more than he had received. Freedom of testation, furthermore, was not complete: a man was obliged to leave a certain proportion of his property to his children and in some cases to ascendants and brothers and sisters.

With regard to intestate succession, or succession without a will, those first entitled in early times were the deceased’s own heirs—that is, those who were in his potestas or manus when he died and who were freed from that power at his death. Failing these heirs, the nearest agnatic relations (relations in the male line of descent) succeeded, and, if there were no agnates, the members of the gens, or clan, of the deceased succeeded. Later reforms placed children emancipated from potestas on an equal basis with those under potestas and gradually gave the surviving spouse (in marriage without manus) greater rights of succession. By Justinian’s day the system had evolved as follows: descendants had the first claim, and failing these heirs, came a composite class consisting of ascendants, brothers and sisters of full blood, and children of deceased brothers and sisters. Next came brothers and sisters of the half blood and, finally, the nearest cognates (relations in the female line). Husband and wife were not mentioned, but their old rights were kept alive in the absence of any of the preceding categories. Justinian also gave a “poor” widow a right to one-quarter of her husband’s estate unless there were more than three children, in which case she shared equally with them. If, however, the heirs were her own children by the deceased, she received only a ususfructus (life interest) in what she took.

The law of procedure

The earliest law suits (legis actiones) were conducted orally in two stages: a preliminary one before the jurisdictional magistrate, in which the issue was developed; and then the actual presentation of evidence to the judex, or judge. The first stage required that set forms of words be spoken by the parties and, sometimes, by the magistrate. The parties making an assertion of ownership, for instance, would grasp the thing in dispute and lay a wand on it, after which the magistrate would intervene and say, “Let go, both of you.” So formal was the procedure that a plaintiff who made the slightest mistake lost his case. For the second stage, before the judex, there were no formal rules. However, the plaintiff had the burden of proof, was responsible for physically producing the defendant in court and, often, for carrying out the sentence.

Under new procedures developed in the 2nd and 1st centuries bce, the issue at the magisterial stage was formulated in written instructions to the judex, couched in the form of an alternative: “If it appears that the defendant owes the plaintiff 10,000 sesterces, the judex is to condemn the defendant to pay the plaintiff 10,000 sesterces; if it does not so appear, he is to absolve him.” A draft of these written instructions was probably prepared for the plaintiff before he came into court, but there could be no trial until it was accepted by the defendant, for there was always a contractual element about a lawsuit under both the new and the old systems. Pressure, however, could be exercised by the magistrate on a defendant who refused to accept instructions that the magistrate had approved, just as a plaintiff could be forced to alter instructions that the magistrate had disapproved, by the magistrate’s refusal to otherwise give the order to the judex to decide the case.

In late republican times, still another system developed, first in the provinces, then in Rome. Under the new system the magistrate used his administrative powers, which were always considerable, for the purpose of settling disputes. He could command: thus if one person brought a complaint against another before him, he could investigate the matter and give the order he thought fit. As imperially appointed officers superseded republican magistrates, this administrative process became more common. The result was that the old contractual element in procedure disappeared as did the old two-stage division. Justice was now imposed from above by the state—not, as originally, left to a kind of voluntary arbitration supervised by the state.