In many ways, the Roman Empire was a sophisticated one, in which sea voyages enabled trade and colonization. The risk associated with lengthy sea voyages was immense, with piracy, storms, and varying prices of goods making sea trade extremely speculative. At the same time, there was no denying its economic importance. The greatest cities, from Athens to Rome, flourished on the strength of their ports.
To solve the risk issue, a sophisticated system of maritime insurance developed. Loans at high interest rates took the place of outright insurance, with the significant interest covering cases in which the voyage ended in disaster. In such an eventuality, the loan itself did not need to be repaid.
In the ancient Mediterranean, loans might increase or decrease depending on the season and expected weather conditions. In addition, failure to pay back loans in good faith and under set terms could result in seizure of the boat by the lender.