Metastasio, Pietro, 1698-1782, Italian poet and librettist, whose original name was Antonio Bonaventura Trapassi. A prodigy at poetic improvisation, he became court poet at Vienna in 1729. He wrote melodious lyric verse; a masque, Gli orti esperidi (1721-22); and librettos of many operas, including Didone abbandonata (1724), Artaserse (1730, tr. 1761), La clemenza di Tito (1734, tr. 1811), and Il re pastore (1751, tr. 1765). These librettos were set to music by many composers, including Gluck, Handel, Mozart, Pergolesi, and Rossini. Metastasio, with Apostolo Zeno, whom he succeeded as imperial poet laureate at Vienna, created the rigid opera seria (see opera). His melodrama Attilio Regolo (1750) is generally considered his masterpiece.