The Morean War was the only time Venice defeated the Ottoman Empire in battle
Between 1684 and 1699, the Republic of Venice launched a rare offensive against the Ottoman Empire. While Venice was a declining power, it seized the Peloponnese by exploiting Ottoman exhaustion from the Great Turkish War. It remains the only conflict where Venice emerged victorious against its long-standing Mediterranean rival.
The Morean War, or the Sixth Ottoman–Venetian War, was part of the broader Great Turkish War. While the Ottomans were occupied fighting the Habsburgs in Hungary and Austria, Venice saw a unique opportunity for revanche. The Republic had been losing its Mediterranean possessions for over a century, including Cyprus and Crete, and sought to reclaim its former influence. On 25 April 1684, Venice officially declared war, marking the first time in their history that the Republic initiated the conflict.
Venice faced significant internal challenges, including a depleted treasury and a small, undisciplined army. To compensate, the Republic relied on foreign subsidies, particularly from Pope Innocent XI, and hired thousands of mercenaries from German states like Hannover and Saxony. Despite these efforts, disease proved to be a deadlier enemy than the Ottomans; for instance, the Hannoverian contingent lost 736 men to illness compared to only 256 in combat between April 1685 and January 1686.
Military operations were led by Francesco Morosini, who successfully captured key fortresses including Coron, Navarino, and the capital of the Peloponnese, Nauplia. The campaign was bolstered by the support of local Maniot rebels and experienced foreign officers like the Swedish marshal Otto Wilhelm Königsmarck. By 1687, the Venetians had effectively completed the conquest of the Morea, securing a major territorial expansion. However, this victory was short-lived, as the gains were ultimately reversed by the Ottomans in 1718 following the Treaty of Karlowitz in 1699.
The war highlighted the shifting power dynamics of the 17th century. While the Ottomans remained a formidable force, their traditional military systems, such as the Janissaries and timariot cavalry, were declining in quality. Simultaneously, the Venetian victory was only possible because the Ottomans were overextended on multiple fronts, including against the Russians and the Holy League. Ultimately, the war served as a temporary resurgence for Venice before its final decline as a major Mediterranean power.
Source: Morean War
