Italian city-states such as Milan, Florence and Venice played a crucial innovative role in financial development, devising the main instruments and practices of banking and the emergence of new forms of social and economic organization. In coastal and southern areas, the maritime republics grew to eventually dominate the Mediterranean and monopolise trade routes to the Orient. They were independent thalassocratic city-states, though most of them originated from territories once belonging to the Byzantine Empire. All these cities during the time of their independence had similar systems of government in which the merchant class had considerable power. Although in practice these were oligarchical, and bore little resemblance to a modern democracy, the relative political freedom they afforded was conducive to academic and artistic advancement. The four best known maritime republics were Venice, Genoa, Pisa and Amalfi; the others were Ancona, Gaeta, Noli, and Ragusa. Each of the maritime republics had dominion over different overseas lands, including many Mediterranean islands (especially Sardinia and Corsica), lands on the Adriatic, Aegean, and Black Sea (Crimea), and commercial colonies in the Near East and in North Africa. Venice maintained enormous tracts of land in Greece, Cyprus, Istria, and Dalmatia until as late as the mid-17th century.