JOHN III. (SomEsKI) (1624-1696), king of Poland, was the eldest son of James Sobieski, castellan of Cracow, and Theofila Danillowiczowna, grand-daughter of the great Hetman Zolkiew ski. After being educated at Cracow, he made the grand tour with his brother Mark and returned to Poland in 1648. He served against Chmielnicki and the Cossacks and was present at the battles of Beresteczko (1651) and Batoka (1652), but when the Swedes invaded Poland in 1654 at once deserted to them and actually assisted them to conquer the Prussian provinces in 1655. Next year, however, he again changed coats and helped Czarniecki expel the Swedes from the central Polish provinces. For his subsequent services to King John Casimir, especially in the Ukraine against the Tatars and Cossacks, he received the grand baton of the crown, or commandership-in-chief (1668). He had already (1665) succeeded Czarniecki as acting com mander-in-chief. His military capacities were extraordinary, but he was unscrupulous and absolutely self-seeking.
At the election diet of 1669 he accepted large bribes from Louis XIV. to support one of the French candidates; after the election of Michael Wisniowiecki (June 19, 1669) he openly conspired, again in the French interest, against the king in an hour of the utmost national danger. The plot he had formed with the primate Prazmowski and others was discovered in 1670 and disavowed by Louis; the traitors then appealed to the Elector of Brandenburg against their own countrymen. Two years later they renewed the plot just as the Turks were advancing into Poland; and the king was consequently forced to sign the disgraceful peace of Buczacz (Oct. 17, 1672) whereby Poland ceded to the Porte the entire Ukraine with Podolia and Kamieniec.
Sobieski himself partially retrieved the situation by winning four victories in ten days. The peace of Buczacz was repudiated, and Sobieski defeated the Turks brilliantly at Khotin (Nov. 1o, 1673). The same day king Michael died, and Sobieski, abandoning the frontier to its fate, hastened to the capital to secure the throne. Appearing at the elective diet of 1674 at the head of 6,000 veterans he overawed every other com petitor, and despite the persistent opposition of the Lithuanians was elected king (May 21). He was then obliged to return at
once to the Ukraine. He attempted to negotiate with the Sultan and the Tatar khan; to entrust the whole guardianship of the Ukraine to the Cossacks, and himself concentrate the regulars and militia at Lemberg. The Polish gentry however failed to support him, and he faced the Turk alone, with a few devoted lieutenants. Returning to Cracow to be crowned (Feb. 14, 1676), he renewed the campaign and at last recovered by special treaty two-thirds of the Ukraine, but without Kamieniec (treaty of Zaravno, Oct. 16, 1676).
Sobieski hoped now to establish absolute monarchy in Poland; but Louis XIV. looked coldly on the project and relations be tween France and Poland gradually grew more strained until on March 31, 1683, Sobieski signed the treaty with the Emperor Leopold against the Turks which was the prelude to the most glorious episode of his life, the relief of Vienna and the liberation of Hungary from the Ottoman yoke. The epoch-making victory of Sept. 12, 1683, was ultimately decided by the charge of the Polish cavalry led by Sobieski in person. Poland profited little by this triumph, being left to fight on in the Ukraine with whatever assistance she could obtain from the unwilling and unready Mus covites. The last twelve years of the reign of John III. were a period of humiliation and disaster. A treasonable senate, a muti nous diet, ungrateful allies, surrounded him.
His last campaign (in 1690) was an utter failure, and the last years of his life were embittered by the violence and the intrigues of his dotingly beloved wife, Marya Kazimiera d'Arquien, by whom he had three sons, James, Alexander and Constantine. He died on June 17, 1696, disillusioned and broken-hearted.
See E. H. R. Tatham, John Sobieski (Oxford, 1881) ; Kazimierz Waliszewski, Archives of French Foreign Affairs, 1674-1696, v. (Cracow, 1881) ; Ludwik Piotr Leliwa, John Sobieski and His Times (Pol.) (Cracow, 1882-85) ; Georg Rieder, Johann Sobieski in Wien (Vienna, 1882).