Vittoria Colonna's only poem in terza rima, Triumph of the Cross of Christ, is closely based on Francis Petrarch's Triumph of Eternity, the last of his six Triumphi on the themes of Love, Chastity, Death, Fame, Time, and Eternity. When we think of important authors who influenced Petrarch, Marcus Tullius Cicero immediately comes to mind, but St. Augustine of Hippo is equally vital. An Augustinian gave Petrarch a copy of Confessions that he carried with him everywhere. Like Cicero, Augustine studied rhetoric before converting to Christianity and embarking on a religious path. Augustine's Confessions and Cicero's De Amicitia are arguably the most influential works on Petrarch's Canzoniere and Triumphi. Both explore the importance of human relationships and true friendships, specifically those that mutually foster virtue and good will. By grounding Ciceronian friendship in God, Augustine renders it mutually salvific. For example, in the second chapter of the Triumph of Death, Petrarch's muse Laura reveals that she reciprocated the poet's feelings but remained distant to preserve their virtue and chastity. It is thanks to her guidance that Petrarch glimpses the beautiful vision of Eternity he writes about in the last triumph. This paper will show how the Augustinian concept of friendship clarifies Laura's salvific role in Petrarch's life and, by extension, the role of Colonna's husband, Ferrante d'Avalos, in her poetry. Augustine emphasizes the inter-relational nature of human experience; he encourages friendships mediated by the divine, seeing our relationship with God through the lens of friendship itself and the necessity of our dependence on one another to reach salvation. It is through this lens that I will examine Colonna's Triumph of the Cross beside Petrarch's Triumph of Eternity. I will also highlight the male-female aspect of these different friendships: Augustine and his mother Monica; Petrarch and his muse Laura; and Colonna and her husband (mio bel sol).