A sorceress in ancient Tuscany who is said to have composed a learned work on the nature of prognostications, especially those concerning thunder and lightening. The work is claimed to be irretrievably lost. There are those who believe that this Bigois may be the 
Bagoe, the Erithryean sibyl, who practice the diviner’s art in Tuscany, but this is sure speculation. A.G.H.

Source: 9.