The study presents from all possible aspects the activity of the Florentine banker F. Benzini at Piran. At his arrival Benzini made a contract with the city in which his monopoly was assured over lending money by documents and by Lombardie manner; he was exempt from taxes and other obligations, as well as the rate of interest of 20 % per year was stated. The actual rate of interest must have been much higher, so that Piran attempted to seize his inheritance after Benzini’s death at the time of pestilence, what would enable the city to remunerate the damage that was done to the citizen because of his usury. In spite of this the money which Benzini had brought with him undoubtedly strongly increased pecuniary exchange and economic investments of citizen of Piran.