This small, gilt brass quadrant is provided with a red leather case lined with velvet of the same colour. On the front of the quadrant are a small compass and a scaphe sundial with a small cover. At the centre is a small relief depiction of a mask. On the opposite face are a horary quadrant for a latitude of 42? (Rome), and a magic square.
This precious instrument belonged to Pope Gregory XIII. The author, Giovanni Battista Giusti, was an instrument maker in Florence during the 1560s.
