A saint's life, like "The Second Nun's Tale," is a biography, but a biography of a very specific type. It's concerned only with the events of the saint's life that serve as evidence of that saint's holiness. So, in "The Second Nun's Tale," we learn next to nothing about Cecilia's parents, her childhood, her education, her likes and dislikes...that stuff isn't important. What's important is how Cecilia lived her faith, and that's the stuff that makes the cut. We hear about Cecilia's marriage because through it, she manages to remain a virgin and convert her husband and brother-in-law. And we watch Cecilia's showdown with Almachius because this proves her steadfast faith in the face of persecution. We also see other characters confirm Cecilia's holiness both explicitly – like when Urban praises her conversion of Valerian – and implicitly – in the many nameless converts Cecilia inspires. These characters exist in "The Second Nun's Tale" for one reason and one reason only: to testify to Cecilia's holiness. Which in the end, is the same reason the written saint's life itself exists.