Contraliterae or export permits are an important historical source that contains traffic data within the coastal area of the Venetian Republic, as well as other ports in the Adriatic and Mediterranean, which have not been subject to management of the Signoria. Due to its geographic position, the eastern Adriatic coast was close to the three great powers: the Venetian Republic, Ottoman Empire, and the Habsburg Monarchy. For a number of years, Venice had, for the most part, in the Middle Ages, managed the transport of people and goods, and has played a significant role as a mediator in the naval trade business between Western Europe and Levant. The biggest competitor to Venice in terms of maritime trade on the Adriatic at the time was the Republic of Dubrovnik. By acquiring coastal cities on the eastern Adriatic coast, the Venetians seemingly secured their status as a naval power. Historical circumstances changed in the 15th and 16th century, for example, the expansion of the Ottoman Empire to the hinterland of Dalmatian towns, as well as parts of the coast, the strengthening of the Habsburg harbors in Kvarner, and the professional diplomacy of the Dubrovnik Republic threatened the dominant Venetian Adriatic trade. The Ottoman conquest of the Dalmatian hinterland and coastal parts in the 15th and 16th century will start to direct a large part of trade between East and West, which during the 16th century, will be increasingly focused on the transportation of goods between the the coasts of the Adriatic sea. Consequently, by studying the contraliterae, some of the changes in trade can partly be followed, which are caused by a wider context of the historical changes in the relationship between the Venetian Republic and its colonies, as well as relations between Venice and other European powers.