Sigismund III, detail of a painting, school of Rubens; in the Bavarian State Picture Galleries, Munich, Germany.Courtesy of the Bayerische Staatsgemaldesammlungen, Munich
Although Poland remained neutral in the Thirty Years’ War (1618–48), Sigismund stealthily supported the Habsburgs, a policy that contributed to a war with Turkey. Poland suffered a major defeat at Cecorą in 1620 but was victorious at Chocim (now in Khotyn, Ukraine) and negotiated peace a year later. The victory at Chocim was memorialized by poet Wacław Potocki a half century later.
The Thirty Years' War.Encyclopædia Britannica, Inc.
There was, however, no real peace with Muscovy, then going through its Time of Troubles. The support extended by some Polish magnates to the False Dmitry (who claimed to be the son of Ivan the Terrible) eventually embroiled Poland in hostilities. The victory at Klushino in 1610 by Hetman Stanisław Zółkiewski resulted in a Polish occupation of Moscow and the election by Moscow’s boyars of Sigismund’s son Władysław as tsar. Sigismund’s veto wasted this opportunity and instead left a residue of Russian hatred of Poland.
Suspicions that Sigismund’s policies were guided by his dynastic interests contributed to a domestic confrontation: the 1606–08 rokosz (“rebellion”). Accusing the king of absolutist designs, the rokosz brought together sincere reformers (who demanded the “execution” of the laws), Roman Catholics, and Protestants, as well as magnates pursuing their own ends. Although the royal forces triumphed in battle, both the king and the reformers were losers in the political realm to the magnates posing as defenders of freedom. Władysław IV
Władysław IV Vasa (reigned 1632–48) continued his father’s policy of strengthening the monarchy and of insisting on the rights to the Swedish throne. Some of the bellicose plans he formulated to increase his power were thwarted by the Sejm and by international circumstances. The anti-Turkish crusade he planned, however, in which Cossacks were to play a major role, contributed to the upheaval that shook the Commonwealth between 1648 and 1660—the uprising in Ukraine and war in the northeast.
Władysław IV Vasa, detail of a painting by Tommaso Dolabella after a portrait from the Rubens atelier; in the State Collections of Art in the Wawel, Kraków, Poland.Pedzlem rozmatiym
Transferred as a result of the Union of Lublin from the grand duchy of Lithuania to the more ethnically homogeneous Crown, Ukraine was “colonized” by both Polish and Ukrainian great nobles. Most of the latter gradually abandoned Orthodoxy to become Roman Catholic and Polish. These “little kings” of Ukraine controlled hundreds of thousands of “subjects” and commanded armies larger than those of the regular Crown troops. In 1596 the Union of Brest-Litovsk subordinated the Orthodox church" class="md-crosslink">Eastern Orthodox church of the Commonwealth to the papacy by creating the Eastern rite (Uniate) church.
Politically, this was intended to cement the cohesion of the state vis-à-vis Moscow; instead it led to internal divisions among the Orthodox. The new Eastern rite church became a hierarchy without followers, while the forbidden Eastern Orthodox church was driven underground. Władysław’s recognition of the latter’s existence in 1632 may have come too late. The Orthodox masses—deprived of their native protectors, who had become Polonized and Catholic—turned to the Cossacks. The Cossacks
The Zaporozhian Cossacks were frontiersmen who organized themselves in a self-governing centre at modern Zaporizhzhya, Ukraine, first to resist Tatar raids and then to plunder as far away as Constantinople (modern Istanbul). Their prowess was recognized by Sigismund Augustus and Báthory, who “registered” a number of Cossacks for military duty. Other Cossacks and all those diverse groups of settlers or tenants whom the lords tried to turn into serfs coveted this privileged status. Even small nobles and burghers resented the heavy-handed behaviour of the “little kings,” who were bent on realizing maximum profits and employing Jews as middlemen and overseers. Growing socioeconomic antagonisms combined with religious tensions.
In the Polish-Turkish war of 1620–21, the victory in the Battle of Chocim had been largely due to the participation of some 40,000 Zaporozhian Cossacks, whom Petro Konashevych-Sahaydachny had brought to aid the Poles. Nonetheless, some 12 years later Cossack demands to be placed on an equal footing with the szlachta were contemptuously rejected by the Sejm. The king and the magnates needed the Cossacks in wartime but feared them as an unruly and seditious group that was embroiling the Commonwealth in hostilities with Turkey and the Tatars. Complaints about the enlargement of the military register and about mistreatment led to several Cossack uprisings. After the rebellion of 1638 was put down by Polish troops, Cossack privileges were greatly curtailed.
The undertaking of an anti-Turkish crusade opened new vistas. There was talk of massive Cossack participation, provided that some 20,000 men be “registered,” social grievances redressed, and a military border free of Polish troops established. Whatever the exact encouragements proffered by Władysław IV, the Sejm and the szlachta were adamantly opposed and frightened lest the king use the Cossacks for his own ends. Bohdan Khmelnytsky
In 1648 Bohdan Khmelnytsky, whom contemporaries likened to Oliver Cromwell, assumed the leadership of the Zaporozhian Cossacks and, allied with the Tatars, defeated the troops of the Commonwealth and some magnate contingents. Khmelnytsky became the master of Ukraine, and its peasant masses, many of its townsmen, and even lesser noblemen were among his followers. The city of Kiev hailed him as a prince and the defender of the Orthodox faith. His objective became the creation of a separate Ukraine under the direct rule of a king.
In Poland, where the sudden death of Władysław IV left the country leaderless, a policy of compromise represented by the chancellor, Jerzy Ossoliński, and the last Orthodox senator, Adam Kisiel (Kysil), clashed with warlike operations of the leading “little king,” Prince Jeremi Wiśniowiecki. The nature of temporary agreements, which intervened between the Commonwealth and the Cossacks, varied depending on the changing fortunes of war. The Polish victory at the Battle of Beresteczko in 1651 was followed by the pact of Biała Cerkiew, which the Cossacks found hard to accept.
In 1654 Khmelnytsky submitted to Alexis" class="md-crosslink">Tsar Alexis in the Pereyaslav Agreement. Russian historiography characterizes that agreement as the reunification of Ukraine with Russia; the Ukrainians interpret it as an alliance based on expediency. At any rate, war began between Muscovy and the Commonwealth, and Alexis’s armies drove deep into Lithuania. In 1655 they occupied its capital, Wilno. For the first time in nearly two centuries, an enemy invasion had taken place, and, when it was followed by a Swedish aggression, a veritable “deluge” overtook the Commonwealth. John II Casimir Vasa
The belligerent and ambitious Charles X Gustav of Sweden worried lest the extension of Muscovy upset the balance of power in the Baltic, which he aimed to turn into a Swedish lake. The refusal of King John II Casimir Vasa, the successor and brother of Władysław IV, to give up his claims to the Swedish crown offered a good pretext for resuming hostilities with the Commonwealth. Aiming originally to seize Polish and Prussian harbours, Charles Gustav saw, after the first successes, the possibility of gaining the Polish crown and the mastery of the Commonwealth.
The magnates and gentry of Great Poland capitulated to the Swedes in July 1655. Prince Janusz Radziwiłł, a leading Calvinist and the greatest magnate of Lithuania, hard-pressed by the Russians, broke off the union with Poland and signed one with Sweden. His motives were a combination of Lithuanian and Protestant interests coloured by his own ambition to rule the grand duchy.