The Holy See Towards the Contention for the Polish-Lithuanian Throne Between the Representatives of the Vasa Dynasty: John Casimir and Charles Ferdinand (1648-1649)

On 21 May 1648, the apostolic nuncio Giovanni De Torres reported from Słonim on the death of Ladislaus IV Vasa, announcing at the same time that the royal halfbrothers John Casimir and Charles Ferdinand would be the most serious candidates for the throne. The papal diplomats frequently emphasised the universal wish of the nobility for a dynastic continuation within the Polish Vasas. At the same time, this was the first time brothers competed for the throne in early modern Poland-Lithuania. It could have caused concern, as everything pointed to a lack of agreement between the contenders, especially in the context of the then-ongoing conflict withthe Cossacks. In this article, the policy pursued by the Holy See towards the election of 1648 is analysed, revolving not only around the personal choice of the monarch but also the issues of the war in Ukraine, the revindication of the Swedish crown, relations with France, Habsburgs and Brandenburg as well as the Polish-Lithuanian Commonwealth's religious policy. The diplomatic letters exchanged between the nuncio and the papal Secretariat of State, the correspondence of the Vasa princes with Innocent X and the sejm accounts constitute the historical basis for the study.