This simplified drawing illustrates the geocentric model of Claudius Ptolemy (fl. 140 A.D.). No attempt has been made to represent the relative size of epicycles and deferents, nor are radial dimensions drawn to scale. Attention is directed to the parallel positions of the radius vectors of the epicycles of the superior planets (Mars, Jupiter, Saturn), and to the ‘sun linked’ motions of the inferior planets (Venus, Mercury).