(1733–35), European conflict caused by the two rival claims to the throne of Poland asserted on the death in 1733 of Augustus II, elector of Saxony and king of Poland (1670–1733), by his son Augustus (1696–1763), and by the Polish nobleman Stanislas Leszczynski. Augustus II had been king of Poland from 1697 to 1704, maintaining his office largely through Russian support. In 1704 Stanislas, with the help of Charles XII, king of Sweden, had deposed Augustus II and then had been elected king by the Polish nobility. In 1709, however, Augustus reassumed the throne with Russian aid. On Augustus's death in 1733, Stanislas again claimed the throne and a majority of the Polish nobles, influenced by Louis XV, king of France, who was the son-in-law of Stanislas, reelected the Polish nobleman as king. At the same time Augustus's son also claimed the Polish throne, and a minority of the Polish nobility, influenced by Russia and Austria, then ruled respectively by Anna Ivanovna and Holy Roman Emperor Charles VI, elected him Augustus III, king of Poland, and demanded that Stanislas abdicate. Stanislas refused, and in 1733 a large Russian army invaded and drove him out of Poland. He took refuge in the fortress of the free city of Danzig, to which the Russians laid siege. A French naval and military expedition to raise the siege was a failure. Stanislas maintained his position until June of the following year, when his army surrendered, and he fled to Prussia.

In the meantime, in retaliation for the Austrian support of Augustus III, France in 1733 had declared war on Charles VI. Spain and Sardinia, viewing the war as an opportunity to make territorial gains in Italy at the expense of Austria, which then held large parts of the peninsula, allied themselves with France. Spanish forces invaded Austrian-held Lombardy, Naples, and Sicily. The French invaded the duchy of Lorraine, then part of the Holy Roman Empire, and also engaged in indecisive fighting with the forces of Charles VI on the upper Rhine River.

The war was terminated by the Treaty of Vienna, negotiated in 1735, but not ratified until 1738. The treaty had four principal provisions: (1) Stanislas was to renounce the Polish throne, which was to remain in possession of Augustus III; in return Stanislas became duke of Lorraine and Bar, both of which duchies were to revert to France after his death; (2) the deposed Francis Stephen, duke of Lorraine (later Francis I, Holy Roman emperor), was compensated by being made grand duke of Tuscany; (3) Austria ceded Naples and Sicily to Spain and in exchange received the duchies of Parma and Piacenza, which had come into Spanish possession in 1731; and (4) France, at the instance of Charles VI, guaranteed the Pragmatic Sanction, the agreement, formulated by Charles in 1713, which declared that in default of male issue on his part, the hereditary Habsburg territories, which included the duchy of Austria and the kingdoms of Bohemia and Hungary, were to descend to his daughter Maria Theresa.