Envy is a ubiquitous emotion which plays an important role in human life. This Introduction provides a brief overview of the taxonomy of envy and a chapter-by-chapter synopsis.

Scholars have typically turned to Aquinas’s Summa theologiae for the moral theology of Dante’s Purgatory. However Dante is, in fact, following an older, more conservative tradition of Christian ethics represented by Peraldus’s De vitiis et virtutibus. In the thirteenth century, theologians moved from trying to displace the structuring principle of the seven capital vices with other alternatives to reforming it from within, and Peraldus and Aquinas adopted markedly different approaches to this reform.

Peraldus’s rationale impels him to treat the vices separately, according to disordered love by excess or deficiency (gluttony, lust, avarice, and sloth) or to love of an evil (pride, envy, and anger). Aquinas, by contrast, introduces an Aristotelian anthropology and a new positive teleological frame, enabling him to treat vices and virtues together in terms of shared good objects desired or avoided. A comparative critique highlights the characteristics, including the weaknesses, of Dante’s poetic treatment (which clearly follows Peraldus’s treatise).

The parallel in ethical content between Peraldus and Dante is matched, furthermore, by a parallel in form: Peraldus’s De vitiis invites us to imagine Dante assuming in the Purgatorio the role of a venacular preacher against vice, with the reader envisaged as a Christian sinner.

This chapter reappraises Dante’s relationship with his reader in Purgatorio through the interpretative paradigm of medieval preaching against vice. The terrace of pride is particularly interesting, in this context, as the medieval Church provides its implicit backdrop. The terrace’s centrepiece is Dante-character’s encounter with three prideful souls (Purg. XI, 37–142), and this encounter is framed by the three examples of humility (Purg. X, 34–93) and the twelve examples of pride (Purg. XII, 25–63). This chapter interprets these three groups together as a triptych.

Dante openly acknowledges that he sinned gravely in pride, and he models a spiritual exercise of conversion from pride to humility. As sinner and preacher, he invites his reader to reflect upon the three prideful souls identified (Omberto, Oderisi, and Salvani) and upon the three groups of prideful examples (delineated by the acrostic ‘VOM’) in counterposition with the three exempla of humility (Mary, King David, and Trajan).

Dante’s choice of exempla (which has puzzled critics) becomes understandable when, and only when, we interpret them in relation to each other in terms of his moral purpose for the terrace as a whole.