Knowing that most of Europe is preoccupied with internal struggles, Suleiman launches his wars against Hungary and Rhodes while they're cut off from outside reinforcements. Suleiman wanted to erase the failures of his predecessor, and extend the Ottoman Empire into Europe... The boy king of Hungary had given Suleiman the perfect pretext for war by killing his envoy, and he'd done it at a time when Hungary was especially isolated from the rest of the continent. The Holy Roman Empire and Papal States were being torn apart by the declarations of Martin Luther. Spain and France were busy fighting each other. Suleiman even ensured that Venice would stay out of the dispute by offering them a lucrative trade treaty with his empire. Though he felt certain of victory, he still studied every route and painstakingly worked out the logistics of moving his army. He would not risk failure through carelessness. Yet the siege from his cannons could not bring down the walls of Belgrade, so he turned to treachery: eventually, the Orthodox Serbian contingent in the city gave him access in order to escape the oppression of the Catholic Hungarians. Suleiman massacred the Hungarians, but honored his agreement with the Serbs and let them leave. Then he turned to Rhodes. He offered them a chance to surrender in advance, but they refused. The Knights of Rhodes were after all a sacred order, equal in discipline to his janissary forces. They fought hard, repulsing several attempts by the Turks to invade through collapsed walls and repeatedly refusing Suleiman's offers to let them surrender. But at last they wore down and agreed to terms of truce. Suleiman allowed them to leave along with any Christian subjects who wished to go with them. It had taken him two years to complete his wars, but he had succeeded.