Giovanni Battista was a Third Class Maintainers in the Tower. He went through it entirely with Milena around 450 AT 1), to finally come out in a different existential plane 2). A quay bore his name on the North Shore of Urbicande 3).
There also has been in our world an Italian architect named Giovanni Battista Piranesi.
Looking arrogant in a painting in L'Archiviste. In the painting he is accompanied by his friends:
Giovanni Battista looks very much like the famous Orson Welles of our world.