A peasant-born former opera star who loses his voice, becomes a Naples music teacher, and recognizes Tonio’s exceptional potential.

Tonio’s exiled older half-brother, disinherited after disgracing the family, whose return threatens Tonio’s expected place in the Treschi household.

Tonio’s elderly father, a Venetian noble and member of the Council of Three, who expects his youngest son to continue the family line.

A fellow castrato boy at the Naples conservatory who becomes personally close to Tonio during his adjustment to that community.

An English noblewoman, widow, and painter whom Tonio encounters as his life expands beyond the Naples conservatory.

A powerful Roman cardinal who becomes Tonio’s patron as the young singer enters Rome’s operatic world.

A powerful Florentine count whom Tonio befriends in Rome, distinct from Cardinal Calvino, the singer’s ecclesiastical patron.