SIGISMUND I. (1467-1548), king of Poland, the fifth son of Casimir IV. and Elizabeth of Austria, was elected grand-duke of Lithuania on Oct. 21, 15o5 and king of Poland on Jan. 8, 1506. He had served his apprenticeship in the art of government first as prince of Glogau and subsequently as governor of Silesia and mar grave of Lusatia under his elder brother Wladislaus of Bohemia and Hungary. His little principality of Glogau soon became famous as a model state, in the prevailing anarchy of waning principalities, and as governor of Silesia he suppressed the robber knights with an iron hand, protected the law-abiding classes, and revived commerce. In Poland his first step was to recover control of the mint, and place it in the hands of capable middle-class merchants and bankers, like Caspar Beer, Jan Thurzo, Jan Boner, the Betmans, who reformed the currency and opened out new ways for trade and commerce. In foreign affairs Sigismund was largely guided by the Laskis (Adam, Jan and Hieronymus), Jan Tarnow ski and others, most of whom he selected himself. His first wife, whom he married in Feb. 1512, was Barbara Zapolya, daughter of Stephen Zapolya of Hungary. On Barbara's death three years later without male offspring, Sigismund (in April 1518) married the beautiful and wealthy Bona Sforza, a kinswoman of the emperor and granddaughter of the king of Aragon, who used her great financial and economic talents almost entirely for her own benefit, corrupted society, degraded the clergy, and became universally detested.
During the first twenty years of his reign, Sigismund was almost incessantly at war with Muscovy. The Tatars too, ravaged the border with a frequency which ultimately led to the establishment of the Cossacks. (See POLAND: History.) Protracted quarrels,
again, with the grand-masters of the Teutonic Order, who were anxious to shake off Polish suzerainty led to a war in 1520-21, but were composed in 1525 when the last grand-master professed Lutheranism and as first duke of Prussia did public homage to the Polish king in the market-place of Cracow.
Personally a devout Catholic, Sigismund was nevertheless too wise and just to permit the persecution of non-Catholics; and in Lithuania, where a fanatical Catholic minority of magnates domi nated the senate, he resolutely upheld the rights of his Orthodox subjects, and protected the Jews.
After his 6oth year there was a visible decline in Sigismund's energy and capacity. His gigantic strength and herculean build lent him the outward appearance of health and vigour, but during the last two-and-twenty years of his reign he apathetically resigned himself to the course of events. He died on April 1, 1548. By Bona he had five children—one son, Sigismund Augustus, who succeeded him, and four daughters, Isabella, who married John Zapolya, prince of Transylvania, Sophia, who married the duke of Brunswick, Catherine, who as the wife of John III. of Sweden be came the mother of the Polish Vasas, and Ann, who subsequently wedded King Stephen Bathory.