Stanislas I. Leszczynski, king of Poland, born in Lemberg, Galicia, Oct, 20, 1677, died in Luneville, France, Feb. 23, 1766. He was palatine of Posen, and had held an office at the Polish court, where he won the friendship of Charles XII. of Sweden, who in 1705, after defeating Augustus II., procured his election to the throne of Poland; but he lost the crown by Charles's defeat at Poltava in 1709, when Augustus was restored. While attempting to join Charles at Bender, Stanislas was in 1713 taken prisoner by the hospodar of Moldavia and delivered to the Turks; released in 1714, he served as governor of Zweibrucken till the death of Charles XII. in December, 1718. The regent Philip of Orleans now granted him a pension and permission to reside at "Weissen-burg, Alsace. His prospects improved in 1725 through the marriage of his daughter Maria with Louis XV., who initiated, after the death of Augustus II. in 1733, a war for the Polish succession; but Augustus III. retained the throne through Russian intervention, although Stanislas had been reelected as king.

The latter was obliged to retire to Dantzic, where he was besieged by a Russian army, and after a bold resistance of several months escaped in June, 1734. In accordance with the preliminary peace of 1735 he resigned his claims to the Polish throne, but retained his royal title, recovered his estates, and received Lorraine and Bar, which after his death were to be united to France; and in the interval he received a pension of 2,000,000 francs for relinquishing the revenues of those duchies. His brilliant court at Luneville and Nancy became celebrated through his munificent patronage of public and charitable works, of letters and art, and through his associations with Voltaire and other eminent personages. Nancy is indebted to him for her finest monuments, and he was styled le bienfaisant. His death was caused by his garments taking lire while he was reading. His essays on philosophy, politics, and morals have been printed under the title of (Oeuvres du philosophe bien-faisant (4 vols. 8vo and 4 vols. 12mo, 1765).