Law of obligations
The law of obligations is one branch of private law under the civil law legal system and so-called "mixed" legal systems. It is the body of rules that organizes and regulates the rights and duties arising between individuals. The specific rights and duties are referred to as obligations, and this area of law deals with their creation, effects and extinction.
An obligation is a legal bond (vinculum iuris) by which one or more parties (obligants) are bound to act or refrain from acting. An obligation thus imposes on the obligor a duty to perform, and simultaneously creates a corresponding right to demand performance by the obligee to whom performance is to be tendered.
Justinian first defines an obligation (obligatio) in his Institutiones, Book 3, section 13 as "a legal bond, with which we are bound by necessity of performing some act according to the laws of our State." He further separates the law of obligations into contracts, delicts, quasi-contracts, and quasi-delicts.
Nowadays, obligation, as applied under civilian law, means a legal tie (vinculum iuris) by which one or more parties (obligants) are bound to perform or refrain from performing specified conduct (prestation). Thus an obligation encompasses both sides of the equation, both the obligor's duty to render prestation and the obligee's right to receive prestation. It differs from the common-law concept of obligation which only encompasses the duty aspect.
Every obligation has four essential requisites otherwise known as the elements of obligation. They are:
- the obligor: obligant duty-bound to fulfill the obligation; he who has a duty.
- the obligee: obligant entitled to demand the fulfillment of the obligation; he who has a right.
- the subject matter, the prestation: the performance to be tendered.
- a legal bond, the vinculum juris: the cause that binds or connects the obligants to the prestation.
Obligations arising out of the will of the parties are called voluntary, and those imposed by operation of law are called involuntary. Sometimes these are called conventional and obediential. The events giving rise to obligations may be further distinguished into specified categories.
- unilateral promise (pollicitatio) - undertaking by promisor only to perform, not requiring the agreement of the beneficiary
- negotiorum gestio - duty to repay someone (gestor) who has managed the affairs or property of another who was unable
- solutio indebiti - undue payment or delivery of a thing to another, who is then obligated to return the thing
A contract can be broadly defined as an agreement that is enforceable at law. Gaius classified contracts into four categories which are: contracts consensu, verbal contracts, contracts re, and contracts litteris. But this classification cannot cover all the contracts, such as pacts and innominate contracts; thus, it is no longer used.
Quasi-contract is one of the four categories of obligation in Justinian's classification. The main cases are negotiorum gestio (conducting of another person's affairs without their authorisation), unjust enrichment, and solutio indebiti.
The designation comprised a group of actions of no obvious similarity, classified by Justinian as analogous to delictual obligations. It includes res suspensae, things po ured or thrown, shippers/innkeepers/stablekeepers, and erring judges.
Obligations are classified according to the nature of the performance (prestation):
- real obligations - undertakings to give or deliver property, possession, or enjoyment 
- specific real obligation - delivery of a determinate thing when it is particularly designated or physically separated from all others of the same class
- generic real obligation - delivery of a generic thing
- personal obligations - undertakings either to do or not do all kinds of work or service
- positive personal obligation - performance
- negative personal obligation - forbearance
The word originally derives from the Latin "obligare" which comes from the root "lig" which suggests being bound, as one is to God for instance in "re-ligio". This term first appears in Plautus' play Truculentus at line 214.
Obligations did not originally form part of Roman Law, which mostly concerned issues of succession, property, and family relationships. It developed as a solution to a gap in the system, when one party committed a wrong against another party. These situations were originally governed by a basic customary law of revenge. This undesirable situation eventually developed into a system of liability where people were at first encouraged and then essentially forced to accept monetary compensation from the wrongdoer or their family instead of seeking vengeance. This signaled an important shift in the law away from vengeance and towards compensation. The state supported this effort by standardizing amounts for certain wrongs. Thus the earliest form of Obligation law derives out of what we would today call Delict.
However, it is important to note that liability in this form did not yet include the idea that the debtor "owed" monetary compensation to the creditor, it was merely a means of avoiding punishment. If the debtor or his family didn't have the means to pay then the old rules still applied as outlined in the twelve tables specifically table 3. This section, despite how harsh it may appear to us, was originally developed as a means to protect debtors from the excessive abuses of creditors.
- Albanese, Bernardo. "Papimano e la definizione di obligatio in J, 3, 13, pr." (1984) 50 SDHI 166 sqq.
- Justinian. "Institute." Trans. John B. Moyle. (Oxford: Oxford University Press. 1889) at 132
- BAUDOUIN, J.-L., P.-G. JOBIN, & N. VÉZINA, Les Obligations, 6th edn. (Cowansville: Éditions Yvon Blais, 2005), 19.
- "Legal definition of Real obligation". legal-glossary.org. Retrieved 2014-03-09.
- Zimmermann, Reinhard. “The Law of Obligations: Roman Foundations of the Civilian Tradition” (Oxford: Oxford University Press, 1996) at 1
- see for example: Exodus 21.23-25
- Zimmermann, at 2-3
- XII tables, specifically Table III "Debt"
- Zimmermann, at 3