Army of the classical Ottoman Empire in the context of Kapıkulu

The Fall of Constantinople, also known as the Conquest of Constantinople, was the capture of the capital of the Byzantine Empire by the Ottoman Empire. The city was captured on 29 May 1453 as part of the culmination of a 53-day siege which had begun on 6 April.

The attacking Ottoman Army, which significantly outnumbered Constantinople's defenders, was commanded by the 21-year-old Sultan Mehmed II (later nicknamed "the Conqueror"), while the Byzantine army was led by Emperor Constantine XI Palaiologos. After conquering the city, Mehmed II made Constantinople the new Ottoman capital, replacing Adrianople.

The siege of Bihać (Croatian: Opsada Bihaća) was the besieging and capture of the city of Bihać in the Kingdom of Croatia within the Habsburg monarchy, by the Ottoman Empire in June 1592. With the arrival of Hasan-paša Predojević as the Beylerbey of the Bosnia Eyalet in 1591, a period of peace established between Emperor Rudolf II and Sultan Murad III ended and the provincial Ottoman armies launched an offensive on Croatia. Bihać, a nearly isolated city on the Una River that repelled an Ottoman attack in 1585, was one of the first targets. Thomas Erdődy, the Ban of Croatia, used available resources and soldiers to protect the border towns, but the Ottomans managed to take several smaller forts in 1591. As the offensive gained pace, the Croatian Parliament passed a law to permit a general uprising in the country on 5 January 1592 for fighting the Ottomans.

In early June 1592, Hasan Pasha led his troops towards Bihać, which was defended by around 500 soldiers and commanded by Captain Joseph von Lamberg. The siege lasted from 10 June to 19 June, when Lamberg surrendered the city due to a lack of reinforcements and an insufficient number of defending troops. Lamberg, for this act, was later tried for treason. Although under the terms of the surrender its citizens were to be allowed to leave or remain in the city without harm, more than 2,000 civilians were killed and 800 were taken captive after Hasan Pasha's troops entered Bihać. The offensive lasted until June 1593 when Hasan Pasha was killed in the Battle of Sisak, which was the cause for the Long Turkish War (1593-1606).