3 canticles (books): Inferno, Purgatorio, ParadisoJourney of 3 days, from Good Friday to Easter Sunday, 1300Each canticle has 33 cantos; plus intro= 100 cantos in total3 guides: Virgil, Beatrice, St. Bernard of Clairvaux3x3=9: circles of Hell, Purgatory, and Paradise (Paradise 9 circles + Empyrean)Terza rima: a/b/a b/c/bc/d/c etc.