text: Adriatic region From the 14th century, Venice controlled most of the maritime commerce of the Balkans with important colonial possessions on the Adriatic and Aegean coasts. Venice's long decline started in the 15th century, when it first made an unsuccessful attempt to hold Thessalonica against the Ottomans (1423–1430). She also sent ships to help defend Constantinople against the besieging Turks (1453). After the city fell to Sultan Mehmet II, he declared war on Venice. The war lasted thirty years and cost Venice many of the eastern Mediterranean possessions. Slowly the Republic of Venice lost nearly all possessions in the Balkans, maintaining in the 18th century only the Adriatic areas of Istria, Dalmatia and Albania Veneta. The Venetian island of Corfu was the only area of Greece never occupied by the Turks. In 1797 Napoleon conquered Venice and caused the end of the Republic of Venice in the Balkans.
  Early modern period
  Ottoman Empire
  Much of the Balkans was under Ottoman rule throughout the Early modern period. Ottoman rule was long, lasting from the 14th century up until the early 20th in some territories. The Ottoman Empire was religiously, linguistically and ethnically diverse, and, at times, a much more tolerant place for religious practices when compared to other parts of the world. The different groups in the empire were organised along confessional lines, in the so-called the Millet system. Among the Orthodox Christians of the empire (the Rum Millet) a common identity was forged based on a shared sense of time defined by the ecclesiastical calendar, saint's days and feasts.