As a counteraction against the economic pressure of Venice in the Adriatic mercantile trade Dubrovnik made contracts concerning friendship, peace, trade and navigation among others also vvith the Italian cities in the Marks (Ancona, Fano). The author's purpose vvas to establish on the basis of special notary series, called »Debita notariae«, which is to be found in the Historical Archives in Dubrovnik, the share of merchants from the Marks in the credit trade of medieval Dubrovnik. The merchants from Dubrovnik spread with the help of commercial societies (collegantia, societas) their business in various commercial centres in the Marks. Data found in bonds and contracts among commercial societies respond to a number of questions in connection with the intermediary role of merchants from Dubrovnik, in connection vvith the import and export merchandise and in connection vvith various forms of trade.