The subject of Sigismund III Vasa's long-term efforts in the field Giovanni Battista Lancellotti was also responsible for church promotions. He came from the Roman patricians, and after studying law in Perugia, he began his career in the offices of the Roman Curia. Over time, he began to perform the diplomatic mission of the apostolic nuncio at the court of Sigismund III Vasa in Warsaw. Already at the beginning of his five-year service as nuncio in Warsaw, he was awarded several times written expressions of thanks and appreciation for diligent performance his mission not only from Cardinal Secretary of State Francesco Barberini, but also from King Sigismund III, who he submitted his opinion to the Cardinal Protector of Poland in the Vatican. It was in Poland that Lancellotti had the opportunity to further promotion in the form of cardinal. The problem of the ineffective cardinal promotion of nuncio Giovanni Battista Lancellotti by King Sigismund III Vasa has remained unexplored so far.