[The tale of Phebus and Cornide]
Phebus, who makes the days light, had a love called Cornide, whom he loved above all others. But what will happen in love no man knows, as Fortune casts lots. So it befell upon a chance that a young knight took her acquaintance and had of her all that he desired. But a deceitful bird, that she had and kept in her chamber since it was very young, revealed everything that he knew [to Phebus]. This bird, whose name was Corvus, was also then much whiter than any swan. And he, that scoundrel, told Phebus all that he knew of his lady. And he [Phebus] unsheathed his sword in anger, with which he soon killed Cornide.
But afterwards he was extremely woeful and repented of his actions. As a reminder to those who use wicked speech, he took vengeance on this bird. He that was snow-white before, was transformed for ever afterwards to coal-black, as can be seen.
And many men still curse him and call him to this day a raven, by whom men may take as evidence, when he crows, that it signifies some misfortune. Beware, therefore, and speak only the best if you would be yourself1, my good son, as I advise you.
1. possibly meaning at peace with yourself, or, want a peaceful or quiet life