Battle of Nicopolis, (Sept. 25, 1396), a catastrophic military defeat for Christian knights at the hands of the Ottoman Turks that brought an end to massive international efforts to halt Turkish expansion into the Balkans and central Europe.
After their victory at the Battle of Kosovo in 1389, the Ottomans gained control of much of the Balkans under the leadership of Bayezid I, known as "the Thunderbolt." This development led Pope Boniface IX in 1394 to call for a crusade against the rising power of the Muslim Ottoman Turks in southeast Europe. In response to the pope’s call, nobles from across Christian Europe eventually signed up for the venture, including large contingents from France, Hungary, and Germany and from the Knights of the Order of the St. John. Led by Sigismund, King of Hungary, they embarked on the long journey to the Danubian fortress of Nicopolis in modern-day Bulgaria.
From the outset the crusade was riven by disputes of precedence and status. The knights reached Nicopolis in the late summer, ill-equipped to take the fortress by force. After weeks of siege, it was discovered that Bayezid was only hours away at the head of a large army. The crusaders panicked, and despite a council of war, their actions were rash and uncoordinated. The French knights insisted on leading a charge, not fully knowing the size of the Sultan’s army. The charge was initially successful, but Bayezid responded with his reserves. In their rush to secure the glory of victory for themselves, the French knights had become separated from their Hungarian support, and as Bayezid counterattacked they were destroyed. The Hungarians tried desperately to support the French but failed to notice an outflanking move by the Ottoman sipahis (light cavalry). Enveloped, the crusaders were overcome. Sigismund was among the few to escape. After the battle Bayezid had most of his prisoners executed.
Losses: Ottoman, considerable of 15,000; Crusader, most dead or captured of 10,000.