Ferdinand III, 1608-57, Holy Roman emperor (1637-57), king of Hungary (1626-57) and of Bohemia (1627-57), son and successor of Holy Roman Emperor Ferdinand II. After the dismissal and assassination (1634) of the imperial commander Wallenstein, Ferdinand became nominal leader of the imperial forces in the Thirty Years War, but it was the imperial general Gallas who was responsible for the successes that culminated in the victory of Nördlingen (1634). After Ferdinand's accession, however, the war took a disastrous turn. Although anxious for peace, Ferdinand rejected the early peace proposals, but in 1648 he had to assent to the treaties negotiated at Münster and Osnabrück (see Westphalia, Peace of), which virtually ended the central power of the Holy Roman Empire. The emperor and his successors were left only the shadow of the imperial dignity, and their power was restricted to the hereditary Hapsburg dominions. In these dominions—a vast enough empire in themselves—Ferdinand devoted the rest of his reign to healing the wounds of war and to continuing administrative reforms. He was succeeded by his son, Leopold I.