Piccolomini, Ottavio (ōt-täˈvyō pēk-kōlôˈmēnē) [key], 1599–1656, Italian general in the service of the Holy Roman emperor during the Thirty Years War (1618–48). He came of a distinguished Sienese family. After fighting in Bohemia, Hungary, the Netherlands, and Italy, he served under General Wallenstein (after 1627) and was a commander of Wallenstein's bodyguard. He was punished for extortion (1629) but was, nevertheless, among those who urged the reinstatement of Wallenstein, who had been dismissed from imperial service in 1630. Piccolomini distinguished himself (1632) at the battle of Lützen. He later supported the conspiracy that led to Wallenstein's deposition (1634) as imperial commander. He served (1636–39) in the Spanish army and was named duke of Amalfi (1639) for his services by Philip IV of Spain. Rejoining the imperial forces, he was defeated at Breitenfeld (1642), after which he again served the Spanish. Appointed (1648) lieutenant general in the imperial army, his service was terminated by the war's end. He was an imperial plenipotentiary in the negotiations for the execution of the Peace of Westphalia and in 1650 was created prince of Hagenau in the Holy Roman Empire.