The Ptolemy world map is a map of the world known to Hellenistic society in the 2nd century. It is based on the description contained in Ptolemy's book Geography, written . Based on an inscription in several of the earliest surviving manuscripts, it is traditionally credited to Agathodaemon of Alexandria. Perhaps the most significant contributions of Ptolemy's maps are the first uses of longitudinal and latitudinal lines as well as specifying terrestrial locations by celestial observations. The Geography was translated from Greek into Arabic in the 9th century and played a role in the work of al-Khwarizmi before lapsing into obscurity. The idea of a global coordinate system revolutionized European geographical thought, however, and inspired more mathematical treatment of cartography.