Sigismund died in 1548, in the 82nd year of his age, with the character of a wise, and magnanimous prince, notwithstanding that in the latter years of his reign he had become unpopular, owing to the misconduct of his queen Bona, to whom he was dotingly attached. He was succeeded by his son Sigismund Augustus, who had been elected and crowned during his lifetime, and was then only ten years old. The most remarkable events of his reign are the acquisition of Livonia, which voluntarily submitted to Poland in order to save itself from the Muscovite yoke; and the legislative union between Poland and Lithuania, which was effected at the diet of Lublin, 1569. By this arrangement it was agreed that the deputies and senators of both nations elionld deliberate in common. The rights of the Polish nobles were extended to those of Lithuania, and the throne of both countries became equally elective ; yet the laws, finances, and army remained distinct. This union continued until the final dissolution of Poland. Under the reign of Sigismund Augustus the doctrines of the Reforma tion acquired considerable influence in Poland.
The interregnum produced by the death of Sigismund Augustus (1572) was dangerous to the peace of the country, particularly as the election of the new king was embarrassed by religious difference& The diet of convocation however, which assembled in January 1573, enacted that all the religious sects which at that time divided Poland should enjoy equal rights and privileges. The extraordinary address of the French ambassador Monluc, bishop of Valence, secured the election of Henry of Valois, brother of Charles' IX. of France. Henry went to Poland ; but a few months after his arrival, having learned the death of his brother Charles IX., by which he inherited the throne of France as Henry III., he secretly left Krakow (1574), and escaped from his new kingdom. The throne was declared vacant in 1575, and Stephen Battery was elected. Ho was a very remarkable person, who had risen by his great merit from a simple Hungarian noble to the dignity of sovereign prince of Transylvania. Battery defeated in repented battles the Muscovites, retook many towns and districts of Lithuania which had been seized by them, and invaded their own country. His death took place in ]5S6, at the moment when he was making great preparations against Muscovy. His successor was Sigismund III (Vasa), son of the king of Sweden, and nephew by his mother to Sigismund Augustus. Sigismandstrongly attached to the Roman Catholic religion, lost his hereditary dominious, and created a general discontent iu Poland by his complete subserviency to the Jesuits and the house of Austria, as well as by his tendency towards despotism. A civil war ensued ; but the insurgents being defeated, the country was restored to peace. Soon after, Sigismund, taking advantage of the distracted state into which Russia fell after the murder of the pretender Demetrius, declared war against that country; and the Polish general Zolkiewski, having defeated the Muscovite army and an auxiliary Swedish force, entered Moscow ; and concluded a treaty by which Vladislav, eldest son of Sigismund, was elected Czar of Moscow, 1610, on conditions which limited the absolute power that the monarchs of that country hitherto possessed. Sigismund delayed his confirmation of that treaty under various pretences, and in the meantime endeavoured to possess himself of some towns and provinces of Russia. The Muscovites, justly irritated by Sigismund's conduct,
rose in arms, and a war ensued, during which the Polish general maintained himself for a long time against the Muscovite; but was finally obliged to retire. The refusal of the diet to grant the necessary supplies produced insubordination in the army, which was unpaid, and the Russians gained great advantages. Sigismund at last suede an effort, and sent his son Vladislav to recover at the head of an army the throne which was lost through his father's incapacity, and already occupied by Michael Federovich Romanow, who was elected in 1613. Vladislav penetrated to the walls of the capital ; and after an unsuccessful attempt to carry it by storm, occupied a strong position in its vicinity ; but the insubordination of the army hastened the conclusion of a truce of fourteen years, by which the Czar Michael Federovich was recognised by Poland, which retained Smolensk, with other provinces. Among the principal events during the remainder of the reign was the war with the Turks (1620-1), who advanced to the Dniester 400,000 strong under the Sultan Osman, and were bravely held in check by 35,000 Poles and 40,000 Zaporoguo Cossaks. Peace was concluded October 7, 1621, which restored the statu-quo of the two countries. In a war with Sweden, 1625, Poland lost Riga and other towns in Livonia.
Sigismund III. died in 1632, in the 66th year of his age. His son Vladislav IV. was elected without opposition. He was a virtuous and enlightened prince. Immediately after his coronation he marched against the Muscovites, who had invaded the Polish frontiers, and having defeated them, he entered the frontiers of Muscovy, where he occupied several towns. Peace was concluded in 3634, ou terms advantageous to Poland. Poland enjoyed a long peace during the reign of Vladislav, who died iu 1648, at the very moment when a moat dangerous rebellion was breaking out among the Cossaks of the Ukraine. The rebellion raged for many years under John Casimir, the brother and successor of Vladislav, until Chmielnitzki, the chief of the Cossaks, in 1654, applied for aid to the czar of Muscovy, Alexius, who sent a numerous army to his assistance and another force to attack Lithuania. The situation of Poland was already very critical, but the imprudence of the king made it desperate. Charles Gustavus having ascended the thrmie of Sweden in consequence of Chriatina'e abdication, John Casimir's ambassador at Stockholm made a protest against his accession to the throne of Sweden, of which his master was the legitimate heir. Charles Gustavus declared war against Poland., which he entered from Pomerania, and soon overran the whole country, seizing both Warsaw and lirakow. John Casimir had fled before the Swede; and was now in Silesia, and the Poles, captivated with the vigour of Charles Gustavus, sent him a deputation to request him to convoke a diet for the purpose of electing him King of Poland. The reply of the Swede, "that ho required no election, as ho was already master of tho country by conquest," wounded the pride of the nation, which rose cm masse, and under the brave Stephen Czavniecki, expelled the Swedes, and restored John Casimir to the throne.