When Suleyman I ascended the throne, the most powerful state of Europe was the German Empire. The Emperor Charles had very a close relationship with the King of Hungary Lois II. Lois II refused to pay the annual taxes to the Ottomans and he killed the Ottoman ambassadors sent for reconcilation.

Mehmed the Conquerer had been captured Serbia during his campaigns to Europe, but Hungary could not have been conquered, yet. Suleyman I decided to capture Hungary, considering her strategic location and the Ottoman navy besieged Belgrade from the river of Danube. Although the city had been defended very successfully the Ottomans defeated the Hungarians in August 21, 1521. Bali Pasha was appointed as the Belgrade guardian. After this campaign some people from Belgrade sent to Istanbul and a Belgrade village had been established. The conquest of Belgrade was the first conquest of Suleyman I. In the following years, the city had served as an important Ottoman passage to Europe.