In Roman law, contracts could be divided between those in re, those that were consensual, and those that were innominate contracts in Roman law (Contratti innominati (diritto romano)). Although Gaius only identifies a single type of contract in re, it is commonly thought that there were four types of these, as Justinian identifies: mutuum (loan for consumption), commodatum (loan for use), depositum (deposit) and pignus (pledge).
Each varied regarding the expected standards of care, transfer of ownership, and other practicalities stemming from the purpose of each. They all involved the delivery of a physical thing, which was a defining characteristic of such contracts. They were generally supplemented by the stipulatio and an inominate contract, which allowed additional provisions, such as interest, to be added to contracts in re making them more suitable for commercial applications.