The election of Sigismund III to the throne proved to be the greatest blow it was possible to inflict upon Protestanism in Poland. Brought up by his mother, Catherine Jagiellon, in the strictest Roman Catholic doctrines, he made the promotion of the interests of Rome the guiding motive of all his actions. This zeal for Rome outweighed all considerations of prudence or policy; through it ' he lost two hereditary thrones, and brought innumerable calamities on the country which election had handed over to him , "In order to make sure of heaven," said the Emperor Ferdinand, "he has renounced earth." The Protestants called him the "King of the Jesuits," and Sigismund gloried in the appellation. This feeble imitation of Philip II of Spain possessed all the bigotry and zeal of his model without his abilities or strength of character. In all that he did he was ruled by the Jesuits; he bestowed honours only on those whom they favoured, and preferred their advice to that of his wisest counsellors. 'By private interviews, wrote a Roman Catholic historian who was also bishop of Przemysl, 'which they could always command, the Jesuits so bound the king by their solicitations, that he did everything according to their counsel, and the hopes and cares of courtiers had no weight except by their favour.Chief among these advisers of the king was Peter Skarga, one of the most eminent of Polish Jesuits. Born in Masovia in 1536, he was educated at the University of Cracow. where he distinguished himself by winning the "prima Laurea." He then proceeded to Rome, where he entered the society in 1568. He began his preaching at Pultusk, and visited the colleges which Stephen had founded at Riga, Dorpat and Polock; his eloquence was very successful, and even now his sermons are thought highly of in Poland. On the accession of Sigismund he became royal chaplain : he founded a confraternity of St. Lazarus at Warsaw, and many other establishments elsewhere.
Link (here) to full engaging account of the "King of the Jesuits"