Note 3 — CANTO XVI.
Charles Eliot Norton translation
The doubt was occasioned by Guido del Duca’s words (Canto XV.), in regard to the prevalence of evil in Tuscany, arising either from misfortune of the place, or through the bad habits of men. The fact of the iniquity of men was now reaffirmed by Marco Lombardo; Dante accepts the fact as certain, and his doubt is coupled with it.