Gaetano Donizetti, a 19th-century opera composer, is best known for “L’elisir d'amore” and “Lucia di Lammermoor.” On Sunday evening “Pia de’ Tolomei” was given its American premiere and it was a wonderful surprise.

Pia is inspired by a scene in Dante’s “Purgatorio” where pilgrim Dante encounters the shade of Pia, who asks the sojourner to remember her to the world. She was married to Nello Della Pietra, a Ghibelline lord, whose cousin Ghino was in love with her.

In the opera, Pia arranges to have a note sent to her brother Rodrigo, a Guelph, arranging a secret meeting. Ghino intercepts the letter, which he takes as proof of her infidelity. Bice, Pia’s maid, tells Ghino that Pia refuses to see him, which sparks vengeance in Ghino.

The plot is too convoluted to detail here, but the end result is that Nello imprisons Pia for her supposed infidelity and orders her death. Piero, a hermit priest and Pia’s confessor, tells Nello the truth — that Pia has not strayed. Nello rushes to his prison to halt the execution but is too late. In a dramatic aria Pia forgives Nello and begs for peace between Nello and Rodrigo.

Amanda Woodbury, a soprano headed for greatness, sings the role of Pia with conviction and extraordinary technical virtuosity. Her scales and arpeggios were crisp and swift; her ornaments were tasteful and appropriate. She has a tremendous range — from rich lows to dizzying highs.

All the singers were fantastic — and there are just too many to mention individually — but a few stand out. Vera Savage, Pia’s maid, has a rich, mellifluous mezzo voice, facile and colorful. Baritone Valdis Jansons, singing Nello, has a warm, round tone and passionate high notes. He brought pathos and sincerity to a character who is more or less a cad.

Cassandra Zoe Velasco, playing Pia’s brother Rodrigo, was stunning. Her voice is not unlike the great Maria Callas, with the familiar timbre of a mezzo as well as amazing coloratura and dazzling high notes. Velasco's voice is perfect for the role of Rodrigo, but she is petite and, physically, not particularly plausible as a leader of opposition fighters.

The Spoleto orchestra was marvelous, as usual; and the chorus, comprised of Westminster students, was equally excellent.

Aurally, the production was wholly successful; visually, not so much. The setting was changed from 13th-century Siena to 1930s Fascist Italy. A bitter Medieval family feud between Ghibellines (supporters of the Holy Roman Emperor) and Guelphs (supporters of the Pope) would be more personal — son against father, brother fighting uncle — than a grandiose fascist conflict.

The set looked like a game board, and the salon of an affluent woman doesn’t make a realistic prison cell. Plus there were simply too many incongruities. The text says Ghino will plunge a dagger into his breast, but he produces a pistol. The common folk who were meant to oppose uniformed Fascists wore suits and hats. Pia’s confessor — supposedly a hermit and priest — was a decorated military officer.

The whole Fascist business seemed ill-conceived. Better Pia in a floor-length brocade gown and tattered, filthy rags. Not only believable; I might’ve wept.

Reviewer David Friddle has doctorates in organ and choral conducting and directs a professional chamber choir in Rochester, Minn.