So many inspired ideas have gone into War Stories — Opera Philadelphia's O17 festival's pairing of one-act operas by Claudio Monteverdi and Lembit Beecher — does it matter that much if the package didn't come together?

Saturday's opening at the Philadelphia Museum of Art had many high concepts at work: The basic piece, premiered by Gotham Chamber Opera in 2014, pairs war parables from different corners of operatic and human history. Monteverdi's 17th-century Il combattimento di Tancredi e Clorinda is a 23-minute mini-saga about Christian and Muslim warriors battling to the death, only to find out, too late, that the Muslim is the Christian's girlfriend in disguise. Beecher's I Have No Stories to Tell You acts as a postscript, of sorts, portraying a woman who is back from war and is so bottled up with post-traumatic stress disorder (PTSD) flashbacks that her husband is ready to call it quits.

Monteverdi was performed in the Cloisters section of the museum, a contained area with arches dating to 13th-century France, and with acoustical properties that make it one of Philadelphia's most attractive micro-venues. Beecher's opera unfolded on the museum's grand stairway, which is often an acoustical nightmare, but was much less so with the small instrumental ensemble positioned halfway up the stairs and the singers sprinkled about in ways that made dramatic sense. Overall, the evening involved a certain amount of crowd control — Monteverdi was performed twice since the Cloisters are so small, and while one contingent of ticket holders was hearing that, another enjoyed the nearby galleries or hit the bar.

Overall, this movable feast came off well, especially Monteverdi. The piece can be staged in a wide range of approaches; one, I saw, was danced. This one was something of a PTSD flashback, populated with mysterious, malevolent figures in black hoods. Though it's one of Monteverdi's more modest dramatic pieces, the instrumental ensemble led by Gary Thor Wedow conspired to make this feel like a major work, with the cast headed by Cecelia Hall and Craig Verm, all solidly schooled in Monteverdi style.

To say the least, Robin Guarino's staging had great atmosphere, with figures in black hoods seen amid dim lighting. The ending had a wonderfully tender moment when the slain Clorinda is carried from the area by Tancredi. Not until Beecher's opera, though, did one truly appreciate what gifted vocalists Hall and Verm are with highly singable vocal writing, to which the singers brought rich sonic imprints. You make a mental note to hear them both again — with exclamation points.

However, I Have No Stories to Tell You librettist Hannah Moscovitch is hardly the only distinguished playwright to revert to prosaic earnestness when faced with the ultra-succinct demands of chamber opera. Her portrayal of female soldier Sorrel, who is now back home reliving any number of war horrors, emphasized the message over dramatic contour and gave little hint as to what inner barriers were stopping her from achieving full disclosure with her loving husband.

Beecher's score, however, is another matter: Sorrel's inner mental states are explored with instrumental writing that conveys all manner of anxiety (particularly with wiry violin tremolos) mixed in with washes of sound that borders on ambient music, though molded into solidly dramatic events. A small chorus in the background sang explicitly about matters Sorrel could't explain, portraying PTSD as something that hijacks one's soul with unwanted memories that refuse to fade.

The message is important, and the project was definitely worth the effort. But were this being created today — and developed by Opera Philadelphia — might the libretto have been turned back at the border?

War Stories will be repeated at 8 p.m. Sept. 17, 19, 21 and 23 at the Philadelphia Museum of Art, 2600 Benjamin Franklin Parkway. Information: 215 732-8400 or www.operaphila.org.