Societas

Consensu or obligatio consensu or obligatio consensu contracta or obligations ex consensu or contractus ex consensu or contracts consensu or consensual contracts or obligations by consent are, in Roman law, those contracts which do not require formalities.

These contracts were formed by the mere consent of the parties, there being no necessity for any writing or formalities, nor even for the presence of the parties. Such contracts were bilateral, that is to say, they bound both parties to them. Such contracts depended upon the ius gentium for their validity. Such contracts were enforced by praetorian actions, bonae fidei, and not by actions stricti juris, as were the contracts which depended on the old civil law of Rome. The term "consensual" does not mean that the consent of the parties is more emphatically given than in other forms of agreement, but it indicates that the obligation is annexed at once to the consensus, in the contracts of this type.

Justinian's Institutes classify the following contracts as consensu: emptio venditio, locatio conductio, societas and mandatum.

Emptio venditio is a contract of sale. This contract derives its force from the consent of the parties. If, however, they agree to reduce the terms of the contract to writing, then the contract is not complete till it is fully committed to writing. If an earnest had been given, this was forfeited to the vendor if the vendee refused to carry out the contract, and double the value of the earnest was forfeited by the vendor if he did not carry it out. The earnest was considered only as evidence of the contract.

There must be a price fixed and certain for every sale, and this price must consist of a sum of money.

Observations on the above: (1) A sale of a thing at a price to be fixed by a third person is valid if the person does fix a price. (2) The price must be in money otherwise the contract is one of permutatio. This was the view held by the Proculians, the Sabinians considering it to be venditio.

The vendor in a contract of sale had to guarantee the vendee free, undisturbed and lawful possession of the thing sold, and to secure him against latent faults.

The vendee was bound to put the vendor in legal possession of the purchase money.

The contract of sale is completed by the consent of the parties; after this, the thing sold is at the risk of the vendee, who also obtained the advantage of any increase to the object.

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