Zygmunt (Sigismund) III Vasa does not hold an especially honourable place among the kings of Poland. When he ascended the throne in 1586, no-one could have foreseen the future events. From the very beginning, he had a chance of becoming the kind of king that Poland had hoped for since the death of his uncle Sigismundus Augustus, the last of the Jagiellons. Of the two previous royal elections, the first had proved inauspicious and extremely brief, and the second was followed by a short if glorious reign. Henri de Valois, brother of the King of France, fled Poland after a mere four months on the throne; while Stephen Bathory, the Duke of Transylvania, died after a series of spectacular military victories but without producing an heir. The next king had to solve the innumerable problems troubling the entire country.
The young King was related to the Jagiellonian dynasty on the distaff side. His mother was Katharine, sister of Anna and daughter of Sigismund I and Bona Sforza; his father was John of Finland, King of Sweden. From the very outset Sigismund III treated his reign in Poland as a temporary period in expectation of the crown of Sweden. Unfortunately, this had a bearing on his foreign policy. Before the coronation, he expressed strongly anti-Habsburg opinions, which proved decisive in his election to the Polish throne (his supporters were recruited from the anti-Habsburg electorate), whereas after his coronation he started to favour the Habsburgs. He was even suspected of considering giving up the throne of Poland in exchange for Habsburg support in securing the crown of Sweden, which they said they would help him retrieve after his father's death. It turned out that the Protestant Swedes did not want a Catholic king and would rather see his uncle Charles, Duke of Sodermanland, on the Swedish throne. However, convinced of his inalienable right to Sweden, Sigismund began a struggle for that crown that dragged on for over two decades. All his actions as King of Poland were oriented towards the achievement of this one goal. The agreement with the Habsburgs, sealed by a secret treaty between the German house and Sigismund and concerning mutual assistance in the event of a rebellion, entangled Poland in imperial conflicts with Hungary, in spite of the considerable number of Poland's own problems. On the one hand, POland was still engaged in war in the East, supporting Dmitri the Pretender to the throne of Russia (in 1609-1611 Polish armies besieged Smolensk and in 1610 Hetman Stanisław Żółkiewski was victorious in the Battle of Klushino); on the other hand, the country was under the constant threat of a Swedish invasion. This was due to the fact that in 1600 a war broke out for the possession of Livonia, which, joining in an alliance with Charles of Sodermanland, decided to break away from Poland. The reason for this was the omission of the ethnic Livonian nobility when estates were granted to Polish and Lithuanian magnates. The war lasted for over twenty years in two stages (1600-1611 and 1617-1622) and in spite of extremely heavy fighting (a victory by Hetman Jan Karol Chodkiewicz in the Battle of Kircholm in 1605) did not bring the expected results. Under the peace treaty of Mitawa (Mitau), Poland lost part of Livonia including Riga, the port which controlled trade in the estuary of the River Dvina.
During the reign of Sigismund III Poland was drawn into a war against the Turks. The Polish intervention during the Czech and Hungarian rebellion against the Habsburgs brought about Turkish retribution against Poland. This was due to the fact that one of the rebels was Bethlen Gabor, Duke of Transylvania, Sultan Osman II's feudal liegeman. Sigismund's poor analysis of the situation caused a conflict with one of the best trained and greatest armies in the world at the time. The war lasted from July 1620 until October 1621. After a four-month siege of Chocim Castle, which the Turks did not manage to capture, it ended with a peace agreement which restored good relations between the two countries. In addition, the Poles pledged to prevent Cossack forays into Turkish territory, and the Turks vowed to reciprocate with respect to the Tartars.
Apart from involvement in numerous military conflicts, the reign of Sigismund III was also marked by failure to achieve the necessary reforms at home. Reform of the treasury, army and mode of election, though much needed, were not carried out and internal security did not improve. Practically until his death on 30 April 1632, for almost the entire forty-five years of his reign, Sigismund felt a stranger in his mother's home country and endeavoured to return to Sweden, with all his efforts aimed at retrieving the Swedish throne.
