Betulia liberata ("The Liberation of Bethulia") is the title of a libretto by Metastasio which was originally commissioned by Emperor Charles VI and set by Georg Reutter the younger in 1734, and which was subsequently set by as many as 30 composers including Jommelli (1743), Ignaz Holzbauer (1752), Kozeluch (1780), Schuster (1787), Salieri (1821) and most famously Mozart, written in 1771.
The Mozart is the best known, if only because the composer's output receives more examination. The Jommelli may be the greater piece, written as it was by a mature hand. Relatively neglected, both works drew attention in 2010 when they were performed side-by-side at the Salzburg Whitsun and Ravenna festivals under the leadership of Riccardo Muti.
Composed in March–July 1771 when Mozart was 15 years old, K. 118 (74c) is a 140-minute "azione sacra" on a text by Pietro Metastasio tracing the story of Judith and Holofernes from the Book of Judith. It was commissioned by Giuseppe Ximenes, Prince of Aragon, while Mozart was in Padua, Italy, and is the only oratorio he ever wrote. Its two parts comprise sixteen arias, with solo or choral parts, scored for soloists, choir and orchestra. Not performed in Mozart's lifetime, "Betulia liberata" hews stylistically to works by Leonardo Leo and Johann Hasse.