An obligation is a legal undertaking (vinculum iuris) that requires one or more parties (entities) to act or abstain. An obligation thus imposes a benefit obligation on the debtor while creating the right to claim the benefit of the obligated who is to be tendered. The most precise Roman classification of commitments was presented in Justinian`s institutions (not to be confused by Gaius`s instuations) which they classify as obligations arising from contracts (ex contractu), those resulting from crimes (ex maleficio), quasi-contracts (almost ex-exctu) and quasi-offences (almost ex-maleficio).  An example of contractual obligations is the liability of parties to a contract to sell a car. One party is required to transfer ownership of the automobile, while the other is required to pay for it. The conditions that govern each party`s obligations are defined in the treaty, such as: quasi-contracts must be very similar sources of obligations to contracts, but the main difference is that they are not created by a will agreement. The main cases are negotiorum gestio (executing another person`s affairs without his permission), unfair enrichment, and solutio indebiti.  This Roman classification is quite controversial for current standards, as many of these cases would be considered totally different from treaties (especially unfair enrichment) and would rather be considered crimes or special obligations. In addition to the types of specific obligations mentioned above, the contracting parties are required to respect the general principles of the treaty.
For example, all contracting parties are legally required to act fairly with each other. No party should use violence or coercion to create a treaty. Are you able to meet your obligations? I have a duty to attend their wedding. In some cases, contractual obligations can be transferred to a third party. If z.B. one party is responsible for painting the other party`s house, it can charge a third of the task`s execution. This is called contract transfer. In fact, he was not obliged to help him return. According to the laws, quasi-contracts were established in the Middle Ages under an act known in Latin as the assumed indebitatus, which means being in debt or having taken out a debt.