Merlin’s mother in Paolino Pieri’s fourteenth-century La Storia di Merlino.
She became pregnant with Merlin after her body was violated by an Incubus demon. She faced condemnation before a judged named Matteo, but was saved when Merlin revealed the judge’s own flawed paternity.
Source
La Storia di Merlino | Paolino Pieri, c. 1300-1305