Rabanus Maurus [780-856] (De rerum naturis, Book 8, chapter 5): The shape of a disk which is round, and the whole of its head is like a shoe sole. - [Migne/Badke]

Vincent de Beauvais [circa 1190-1264 CE] (Speculum naturale, Book 17.93): The sole fish is, according to the physicians, the most pleasant of the sea fish in food for the sick, because it is less phlegmatic than the others. It is also pleasing to the taste. - [Badke translation/paraphrase]