Astronomicum Caesareum depicts the cosmos and heavens according to the 1400 year old Ptolemaic system, which maintained that the sun revolved around the earth. By means of hand colored maps and moveable paper parts (volvelles), Petrus Apianus (1495-1552) laid out the mechanics of a universe that was earth-centered and human-centered. Within three years of Apianus's book, this view was challenged by Copernicus's assertion that the earth revolved around the sun, making this elaborate publication outdated. A dragon is a legendary creature, typically with serpentine or reptilian traits, that features in the myths of many cultures.