Emperor Frederick III convoked the Imperial Diet to Wiener Neustadt to discuss the possibilities of a new crusade against the Ottomans. At the conference, where the envoys of the Hungarian, Polish, Aragonese and Burgundian monarchs were also present, no final decisions were made, because the Emperor refrained from a sudden attack against the Ottomans. According to Aeneas Silvius Piccolomini, the Emperor hindered Hunyadi from participating at the meeting. In contrast with the Emperor, the new Pope, Callixtus III was a fierce supporter of the crusade.