William II, 1792–1849, king of the Netherlands and grand duke of Luxembourg (1840–49), son and successor of William I. He served with Wellington in the Peninsular War, was wounded at Waterloo, and led the Dutch army in the Belgian revolution (1830), after his father had failed to approve his efforts at conciliation. Called to the throne upon the abdication of his father (1840), William II was immediately confronted with a grave financial problem, which was solved by raising a "voluntary loan" among the people. Demand mounted for constitutional revision, but the king resisted the liberal movement, led by Jan Thorbecke, until the revolutionary spirit of 1848 induced him to grant the desired reforms. He was succeeded by his son, William III.