This project aims for a structural and comparative study of Roman trade, trying to pinpoint which features are essentially Roman and which are shared with other pre-industrial societies. By confronting the organization of Roman trade with medieval and early modern parallels, we will show that many commercial strategies which made trade more efficient (agency, external financing, risk sharing etc.), were already in practice during the Roman empire. By using the rich data sets, records and archives from other pre-industrial societies, we will study both the efficiency and problems in using these commercial strategies. This way, we will be able to trace how (in)efficient Roman merchants were in coping with the difficulties that hampered all pre-industrial commerce (slow transport, the lack of information, finding trustworthy agents etc.). Therefore, we claim that economic history should not be confined to a omparison of medieval and early modern times alone, but should make use of Roman economic history as well. By highlighting the similarities in all stages in pre-industrial commercial organization, we advocate a long-term approach of economic history.