Consensual contracts were introduced by the Romans and proved pivotal in their growth and prosperity as a trading nation. Contracts did exist prior to this point but consensual contracts allowed transactions to take place without property changing hands: there merely needed to be consensus or agreement between the involved parties. There were four types: 'emptio-venditio' was a contract for the exchange of goods; 'locatio-conductio' was a contract for the hire of goods; while 'societas' governed partnerships. The final consensual contract was 'mandatum' which dealt with the commissioning of one party to carry out an activity that would benefit another without reward.
