Berwick, James FitzJames, duke of (bĕrˈĭk) [key], 1670–1734, marshal of France; illegitimate son of King James II of England and Arabella Churchill, sister of the duke of Marlborough. Born and educated in France, he fought in Hungary against the Ottoman Turks. In 1687, his father, who had ascended the English throne in 1685, created him duke of Berwick. When his father was dethroned (1688), Berwick took part in the invasion of Ireland (1689) against James's successor William III; the effort was supported by King Louis XIV of France, James's ally. After the defeat in Ireland, Berwick fought for France in the War of the Grand Alliance and became (1703) a naturalized Frenchman. He subsequently helped suppress the Protestant Camisards. In the War of the Spanish Succession (see Spanish Succession, War of the), he won the decisive victory of Almansa (1707) for King Philip V of Spain, Louis XIV's grandson. In 1709 he campaigned against Prince Eugene of Savoy in defense of the southeastern frontier of France, and his capture of Barcelona (1714) was the closing event of the war. During the War of the Polish Succession, he commanded (1733) the French army of the Rhine; he was killed at Philippsburg.