Sultan Bayezid I ruled the Ottoman Empire for 31 years. There were many wars during his reign. His brother Cem wanted to become sultan of the Ottoman Empire. Cem started a civil war against Bayezid I. The Mamluks supported Cem. But Bayezid I's army won and Cem fleed. The Pope's soldiers captured Cem. Years later, Pope's soldiers killed Cem. After the civil war Bayezid I attacked Kiliya and Bessarabia. The Ottomans captured these regions in 1484. Later that year, theOttomans captured Moldavia. In 1491 - 1495, the Ottomans attacked Mamluk's territory. The Ottomans captured Adana and invaded Southeastern Anatolia Region. But, the Mamluks entered there in same time. In 1495, the war finished. Adana and surrounding districts became part of the Ottoman state. The Ottomans also attacked Central Europe. The Europeans were afraid of this. Bayezid I especially strengthened both the Ottoman army. Ottoman land army and Navy. The Ottomans were strongest in Anatolia and Rumelian. Ottomans enveloped Belgrade again and again. But Ottomans be defeated. Belgrade defeated successfully. Same years, Hungarians attacked Ottomans again and again. 8,000 Ottoman raiders attacked there. But, 40.000 Hungarian soldiers (or over 40.000) road cut. Ottomans wage war with Hungarian's army. Ottoman's 8.000 raiders beat of 40.000 Hungarian soldiers in 1493! All Hungarian army vanished! This was incredible. In 1499, Ottoman armada made sea war with Venice's armada in Mediterranean Sea. Venice's arma defeated by Ottoman's armada. But, Ottoman's army commanders died. A lot of Venice's ships sunk. Ottomans won this war. A few times later Ottomans made peace with Venice. Bayezid I, abdicate to the throne in 1512. And his son Selim I (Yavuz) became emperor of great Ottoman Empire. During he became emperor, Caucasus, Balkans, Rumelian, Anatolia was state of Ottoman empire.