Canto X takes place in circle 6 of Hell where, according to the principle of cotrappasso, the heretics are eternally tormented as they denied the eternity of the soul. The character who makes the prophecy is Farinata Degli Uberti, the leader of the Ghibellines faction in Florence, who twice defeated the Guelphs but couldn't stop them from regaining power both times. As a result of the Guelphs' return, Farinata's family experienced persecution and exile. Although Dante was part of the opposing faction, the Guelphs, the character of Farinata is portrayed with respect. The character prophesizes Dante's own exile from Florence before the moon is crescent for 50 times. The prophecy is in lines 79 - 81:
But the face of the lady reigning here
will be rekindled not fifty times before you too
shall know how difficult a skill that is to learn.
The lady reigning here is an allusion to Persephone and the skill that is difficult to learn is that of returning to one's birthplace from exile.