'Atlas labors under the weight because he had been sentenced by Zeus to hold up the sky. The globe shows a depiction of the night sky as seen from outside the outermost celestial sphere, with low reliefs depicting 41 (some sources say 42) of the 48 classical Greek constellations distinguished by Ptolemy, including, Aries the ram, Cygnus the swan and Hercules the hero. The Farnese Atlas is the oldest surviving pictorial record of Western constellations. It dates to Roman times, around AD 150, but has long been presumed to represent constellations mapped in earlier Greek work.'