The Compactata, one of the most significant documents related to the Council of Basel, have not been analyzed and understood properly in the historiography, both in relation to their content and impact. This article aims to provide a better understanding of the Basel Compactata by discussing the controversial nature of these documents as demonstrated in international diplomacy and polemical writings of the fifteenth century. The diplomatic missions of J. Carvajal, N. Cusanus, J. Capistrano, and E. S. Piccolomini prove that the Compactata could easily have become a crucial bone of contention between Catholics and Bohemian Utraquists even on the international level. Rather surprisingly, the Catholic diplomats’ negative approach toward the Compactata does not appear to have been influenced by their origins in the controversial Council of Basel, for other phenomena such as craving for perfect unity and alleged transgressions of the treaties played a more prominent role. A thorough examination of polemical writings shows that there existed major differences between the standard Catholic and Utraquist interpretation of the key provision of the Compactata, which was possible due to their compromise wording. Such differences could affect considerably the situation in the Czech Lands. For instance, the emergence of a semi-independent Utraquist Church after 1436 was not explicitly stated in the Compactata and was enabled by the manner in which the Utraquists interpreted their text. Although the Compactata did contribute to the stabilization of the political situation in the Czech Lands, unproductive disputes over their meaning actually disturbed the idea of peaceful coexistence between the Catholics and Utraquists.
