For most of us, sacred music provokes a response somewhere on the spectrum between inner calm and drowsiness. But shock? Outrage? Not exactly. For listeners with no more than a passing knowledge of musicological history, the idea that classical music’s earliest composers—writing what strike our ears as innocently pious vocal harmonies—could have found themselves in the cross hairs of scandal seems about as likely as a mosh pit breaking out behind Leonard Slatkin.

But there were days—centuries, really—when every corner of religious practice in Europe held the potential to provoke the kind of nasty controversy that ends up with somebody in jail, exiled, or dead. If it wasn’t exactly the punk rock of the 1600s, early music and its treatment of the relationship between God and man did have the power to make the church establishment very nervous. And just as it has in our era, music often proved a convenient vehicle for cultural fear-mongering.

Those themes make up the compelling backdrop to Jeanne Marshall’s Rapture, which MetroStage is producing at its new 150-seat digs in Alexandria, just a stone’s throw from the Potomac and seemingly even closer, acoustically speaking, to the runways of Reagan National. Combining political intrigue, Catholic doctrine, and some soap-operatic family dynamics, the script is based on the story of a real-life 17th-century nun named Lucrezia Vizzana, who was born in northern Italy and, despite little formal training, composed sacred vocal music that has survived to the present day. In 1995, a professor of music at Washington University in St. Louis, Craig Monson, published an exhaustive book about Vizzana, who entered Bologna’s Santa Cristina at the age of 8 after the death of her mother. She was raised there by her aunts, became a novice at 11, and took her vows at 16.

Though MetroStage’s program notes don’t mention Monson’s book, Rapture—first produced last year at Luna Stage in Montclair, N.J.—is presumably highly dependent on it. This is not to say Marshall hasn’t twisted the facts for her own dramatic purposes, as any canny artist working from a historical template will do. Her biggest change has been to make the young composer a victim of efforts by the convent’s leadership—particularly the conniving Beatrice Bianchi (Laura Giannarelli)—to crush her creative impulses. Marshall’s script drops frequent references to the Vatican’s so-called Seven Rules on the production and instruction of music, dictates that Sister Beatrice and her timid sidekick Maria (Lynn-Jane Foreman) are all too eager to enforce. (They’re scandalized, or pretend to be, by Lucrezia’s compositions, one of which is bold enough to mention Jesus and the word “bedchamber” in the same sentence.) This means that when a local musician named Vernizzi (Gary Telles) shows up to teach Lucrezia he has to sneak around like—well, like a married man inside a convent.

In fact, according to Monson, young Lucrezia’s musical talents were nurtured in a remarkably supportive and open environment. “Santa Cristina,” he writes in the liner notes to a 1998 recording of Vizzana’s motets, “was strongly committed to achieving artistic, musical, and devotional distinction. The convent’s lavishly decorated new public church, and its many talented nun musicians and musical patrons, showcased the singular talents of the budding composer.”

Marshall’s tweaking of the historical record gives her script added dramatic appeal, mostly by providing some villains inside the convent walls rather than way off in Rome. Still, this strategy, with its focus on betrayals and reconciliations within a small group of women, steers the play in a pop-psychological direction. It also raises a substantial logical question: Would an essentially self-taught composer like Lucrezia really have been able to produce long-lasting works without a supportive creative community, without the fellow nuns she clearly relied on in real life to serve as a kind of experimental choir? Could her music have matured had it been performed only in her head?

Marshall has decided to sidestep those questions in an effort to keep the script as circumscribed as possible. More than anything, this is the story of how an all-female society-within-a-society chooses to govern itself, with enough ambition, back-stabbing, and shifting allegiances to fill an entire season of reality television. While the sisters are tending to their tomatoes and hanging their sheets out to dry in the sun, they’re also nurturing decades-old grudges.

Rapture is a very talky play. There are long stretches when the accusations and the explanations fly back and forth from one nun to another. In the first act, as we’re getting our bearings in this foreign landscape, the exposition is helpful: We’re grateful that the characters keep repeating one another’s names, so we can remember which sister is Ortensia and which is Flaminia. And a few of the performers are up to the challenge of so much pure language, particularly the excellent Catherine Flye as Camilla, Lucrezia’s most active protector. As the young composer, Michelle Shupe strikes a good balance between girlish restlessness (she’s dying to get a look outside the convent) and somewhat crazed late-night devotion to her musical craft.

Yet after intermission, once we’ve gotten to know the characters, their alliances, and their foibles, Marshall’s continued reliance on overcooked dialogue begins to take its toll. There are ways for a director of material like this to keep our interest from flagging, by giving the actors visually distracting tasks to carry out, but Diana Denley’s staging, with a few exceptions, is content to have the nuns simply stand their ground while pleading and arguing away. (She also allows her cast to get away with clashing accents.) Dan Schrader’s set is attractively spare, but it gives the actors few places to hide when the script insists they do so, or to engage in physical action. And the performances fall off considerably in the supporting roles, with achingly sincere acting more on display than emotional insight.

And Marshall’s compulsion to overexplain the roots of every conflict between the nuns further weakens the production. We don’t see Beatrice’s dastardly acts, for example, and then try to surmise what in her past might have compelled her to behave in such a way; instead, we get a self-flagellating monologue, straight from a daytime talk show, that spells out every injury to her damaged psyche. Instead of the time to add 2 and 2 to get 4, we’re presented with a 10-page proof from the playwright laying out each teary particular—a dramatic Q.E.D. by way of Oprah. CP