The Cranky Professor is Danteblogging. An excerpt:
Esolen's note reminds us that Virgil addressed Calliope and that Ovid told us the story (Metamorphoses 6.294-340, 662-78). Some foolish humans engaged in a singing match with the muse. She won, of course, and to remind them of their presumption turned them into magpies. No one ever came out ahead in those challenges to the Olympian gods - Arachne, Marsyas, these girls - and no mercy was shown, no chance of forgiveness. Dante is subtle here, reminding us that however much he loved those old poets, he did not love their gods.