Meridiana
The English monk William of Malmesbury described in his eleventh-century chronicles how Gerbert D’Aurillac had made a pact with the devil and while studying in Spain had stolen a precious book from an Arab philosopher there.
Coveting the book’s secrets, Gerbert had seduced the man’s daughter to aid him in his theft. Gerbert was also said to have been in league with a demon, Meridiana, who helped him in his ascendancy to the highest position in the church (he was Pope Sylvester II (999-1003), and that he built a brazen head, which could divine the future.
The World of All Souls, the Complete guide to A Discovery of Witches, Shadow of Night and the Book of Life,
Deborah Harkness
The next part of the text includes small spoilers (if the show follows books in this detail), so if you don’t want to know, stop reading now…:)