MOZART AND JUDITH - The New York Sun has a review of a performance of Betulia Liberata:

Lawfully Wedded Operas
Classical Music

By JAY NORDLINGER
August 22, 2006

For Mozart's 250th-anniversary year, the Salzburg Festival set out to do all 22 of the composer's stage works, and they are. ...

When he was 15, Mozart wrote "Betulia Liberata." It is not exactly an opera, more like an oratorio — more specifically, an "azione sacra," or sacred action, in two acts. Mozart wrote it on a text of Metastasio, the master of opera seria. And that text is from the Book of Judith, which belongs to the Apocrypha.

The story tells of "Betulia liberated" (as Mozart's title has it). What happens is basically this: The Israelite town of Betulia is under siege by an Assyrian army. All seems lost. But Judith, a widow, has a plan. She goes into the enemy camp, makes nice with the leader, and returns with his head — I mean, literally.That's it, in an extremely tight nutshell. The piece, true to its form, gives you recitative and aria, recitative and aria, at length. It may not be Mozart's most inspired work, but it is still Mozart, and not at all bad for a mid-teenager (or for anybody).

The Salzburg Festival presented a single performance of "Betulia Liberata," with no staging. The concert took place on Friday night in the Felsenreitschule, in front of that multi-tier parking garage that serves as the set of "La Clemenza di Tito." The orchestra was a good one: the Munich Chamber Orchestra, led by a good conductor: Christoph Poppen. Mr. Poppen, a German, has been music director of this group for 11 years; his tenure will come to a close at the end of this season.

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And there's more on the performance if you follow the link.