Ptolemy (Claudius of Ptolemaeus) active 150 AD, Alexandrian Greek astronomer and geographer, using quadrant to observe the moon and stars. Urania, Muse of Astronomy, instructs him. Ptolemy is shown wearing a crown as he was sometimes confused with the Ptolemaic kings of Egypt. From 'Margarita Philosophica' by Gregor Reisch (Basle, 1508). Hand-coloured woodcu.