Although the Byzantine Empire for some time did not play a significant role among the European powers, Constantinople had but a still high symbolic value in Christian self-understanding. The victory of the young, dynamic and Islamic Ottoman Empire, triggered a polyphonic debate in Europe, which affected not least his own, Christian self-understanding. So the humanist Nicholas of Cusa wrote directly under the impact of the fall of the city of his work, "De Pace Fidei" ("About the faith Peace"), in which he strongly for an understanding between the religions in general, but in particular between Christianity and Islam, makes. At the same time there were growing in Europe votes that considered "the Turks" as a punishment from God for his own sins. [14] [15] The Greeks had this punishment by their schism, that the retention of the Orthodox faith and the rejection of the Catholic, on accommodated. Against such a punishment from God, but we should not force of arms, but one must overcome one's own sin and seek an orthodox life. These discussions reflect the situation of the European societies. More and more people of the eternal wars and are squabbling princes (the Hundred Years War had ended just a few years earlier) tired. At the same time the church was often as deeply corrupt and rotten with sin. The medieval model of christianitas, the idea that all Christian powers should stand together to conquer the Holy Lands and the spread of the Christian faith, were now so new concepts of communication with "the other", but also the inner self-renewal asserted.
Nevertheless, the case of Constantinople suggested but also to new crusade plans. So Pope Nicholas V called several times on the common fight against the Turks. The imperial advisor Ennea Silvio Piccolomini (later Pope Pius II called the Estates 1454/1455 to three so-called Turkish Empire days of Regensburg, Frankfurt and in the Wiener Neustadt, in order to win the war against the Turks. [16] In Lille Burgundy organized Philip the Good 1454 the so-called pheasant party in which he vowed along with many other knights and nobles take an oath to Türkenzug. [17] won Although the siege of Belgrade was in 1456 by inflowing the crusade calling gefolgten farmers further military action against the Ottomans arose but not after all the oaths and inflammatory speeches.