We are not definitely informed as to just the course of improvement or advancement in early scientific map making among the Greeks, yet not a few names are known to us of those who made it a matter of special endeavor, as they specifically stated, to improve the work of their predecessors. We, for example, are told that Hecataeus (550-480 B. C.),[10] likewise a native of Miletus, improved the maps of Anaximander, and that scientists of his day were astonished at his results; that Dicaearchus of Massina (350-290 B. C.)[11] was the first to employ a central line of orientation on a map, one passing through the Mediterranean east and west, and that he represented on his map all the lands known since the expedition of Alexander the Great into the Far East; and further, that Eratosthenes, the librarian of Alexandria (276-196 B. C.),[12] was the first to attempt a representation of the curved surface of the earth on a plane in accord with geometrical rules. The scientific cartographical ideas of Eratosthenes were further developed by Hipparchus (180-125 B. C.),[13] who is generally referred to as the greatest astronomer of antiquity, and by Marinus of Tyre (fl. ca. 100 A. D.),[14] who introduced the idea of inscribing lines of latitude and longitude on a map, crossing the same at right angles, which lines could be made to serve the useful purpose of orientation and be of assistance in giving proper location to all known places on the earth’s surface. Map making in that early period reached its climax in the work of Claudius Ptolemy of Alexandria (ca. 87-150 A. D.).[15] His ideas, however, seem not to have found general favor with his contemporaries, nor with the geographers of the middle ages. (Fig. 3.) It was not until the so-called period of great geographical discoveries and explorations in the fifteenth century that he became a real teacher within his chosen field. [Illustration: Fig. 3. Ptolemy World Map.] Map making and the science of geography were continuously progressive among the Greeks. Imperial Rome witnessed little progress in either field. Among those who wrote in the Latin language, Pomponius Mela (fl. ca. 43 A. D.)[16] and Pliny (ca. 23-79 A. D.)[17] alone have rank of importance. In the matter of map construction the Romans held to many of the cruder methods and ideas of the Greeks, a fact which we learn from the fragmentary references in their literature, and from the itinerary or road maps (Fig. 4), of the period of the emperors, which have come down to us.[18] [Illustration: Fig. 4. Sections of Peutinger Tables.]