LADISLAUS IV Vasa, king of POLAND. - Son of Sigismund III Vasa, born on 9 June 1595, he skilfully manoeuvred between France and the Habsburgs during the Thirty Years' War. He showed tolerance towards Protestants and turned his particular attention to the Eastern problem, defeating the Russians in the campaign of 1632-34.
His ambition to sit on the Swedish throne found no support among the Poles. After concluding an armistice with Sweden (1635), he was preparing to enter into war against the Turks when death overtook him at Merecz on 20 May 1648, just as the revolt of the Cossacks under Bohdan Chmielnicki was breaking out.
BIBL.: A. Szelagowski, Rozkład Rzeszy i Polska za Wł. IV (Lo sfacelo dell'Impero e la Polonia sotto L. IV), Cracovia 1907; Angelo Tamborra