Witches of Thessaly?

Have the Witches of Thessaly been mentioned much in Ars5? I'm just trying to recall where i have read about them - I'm pretty sure they are in there somewhere?

cj x

Mentioned in the Ex Misc Chapter of Societates (page 109).

They are also an Infernal Society in RoP: Infernal, page 140.

The Infernal too, IIRC.
Edit: Doh! Beaten to it by John Post himself. I feel humbled.