The Mabinogion: Math Son of Mathonwy
14th century, Middle Welsh, National Library of Wales
Math turns his nephews into pigs; Gwydyon into a wild sow and his brother Gilvaethwy into a wild boar.
Math has discovered that his nephews, Gilvaethwy and Gwydyon, have conspired to violate his virgin foot-holder, who is now no longer a virgin. Gwydyon, as the accomplice in this crime, he punishes by turning him into a stag, and his guilty brother Gilvaethwy he turns into a hind. 'Since you are both in league with each other,' says Math, 'you shall go into the forest together and mate with one another, and you shall take on the form of deer.'
So off they go, and a year later return leading a young fawn. Math takes the fawn, changes it back into human shape, but turns his nephews into pigs; Gwydyon into a wild sow and his brother Gilvaethwy into a wild boar. They go off into the forest again and a year later return with a piglet. The youngster is changed into a little boy, but Gwydyon is changed into a wolf and Gilvaethwy into a she-wolf. Off they go again, and only on their return once more with a youngster, a year later, are all three of them changed back into human shape. 'Men,' says Math, 'you have been punished enough for your crime, for it is a great shame and a great humiliation that each of you has born offspring to the other.'