| Emilio, a seminarian | Tenor |
| Mónica, governess in the house of Don Ricardo Medina | Mezzo-soprano |
| Remedios, mother of Emilio | Contralto |
| Doña Fernanda, wife of Don Ricardo Medina | Contralto |
| Don Pedro, priest and confidant of Doña Fernanda | Baritone |
| Raimundo, master of the Medina house | Bass-baritone |
| Don Ricardo Medina, head of the Medina clan | Baritone |
| Alfonso, bookseller and Emilio’s uncle | Bass |
| Diego, son of Mónica and Don Ricardo | Tenor |
| El Señor Raleigh, English traveller, friend of Emilio and Diego | Bass |
| Edward Nelson, Diego’s mentor | Bass-baritone |
| Very Useful, Mr. Nelson’s servant | Baritone |
| Sofia Duarte, daughter of Roberto Duarte | Soprano |
| Don Roberto Duarte, Yucatecan hacendado, bookseller | Bass-baritone |
| Gabriela, wife of Roberto Duarte | Mezzo-soprano |
| Doña Laura, mother of Roberto Duarte | Contralto |
| Aunt Marta, Gabriela’s sister | Mezzo-soprano |
| Don Victor Blanco, henequen magnate | Bass |
| Carlos Blanco, son of Victor Blanco | Baritone |
| Rosita, childhood friend of Sofia | Soprano |
| Patricia, friend of Sofia | Soprano |
