10 · Greek Cartography in the Early Roman World
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10 · Greek Cartography in the Early Roman World PREPARED BY THE EDITORS FROM MATERIALS SUPPLIED BY GERMAINE AUJAe The Roman republic offers a good case for continuing to treat the Greek contribution to mapping as a separate CONTINUITY AND CHANGE IN THEORETICAL strand in the history ofclassical cartography. While there CARTOGRAPHY: POLYBIUS, CRATES, was a considerable blending-and interdependence-of AND HIPPARCHUS Greek and Roman concepts and skills, the fundamental distinction between the often theoretical nature of the Greek contribution and the increasingly practical uses The extent to which a new generation of scholars in the for maps devised by the Romans forms a familiar but second century B.C. was familiar with the texts, maps, satisfactory division for their respective cartographic in and globes of the Hellenistic period is a clear pointer to fluences. Certainly the political expansion of Rome, an uninterrupted continuity of cartographic knowledge. whose domination was rapidly extending over the Med Such knowledge, relating to both terrestrial and celestial iterranean, did not lead to an eclipse of Greek influence. mapping, had been transmitted through a succession of It is true that after the death of Ptolemy III Euergetes in well-defined master-pupil relationships, and the pres 221 B.C. a decline in the cultural supremacy of Alex ervation of texts and three-dimensional models had been andria set in. Intellectual life moved to more energetic aided by the growth of libraries. Yet this evidence should centers such as Pergamum, Rhodes, and above all Rome, not be interpreted to suggest that the Greek contribution but this promoted the diffusion and development of to cartography in the early Roman world was merely a Greek knowledge about maps rather than its extinction. passive recital of the substance of earlier advances. On Indeed, we can see how the conditions of Roman ex the contrary, a principal characteristic of the new age pansion positively favored the growth and applications was the extent to which it was openly critical of earlier of cartography in both a theoretical and a practical sense. attempts at mapping. The main texts, whether surviving Not only had the known world been extended consid or whether lost and known only through later writers, erably through the Roman conquests-so that new em were strongly revisionist in their line of argument, so pirical knowledge had to be adjusted to existing theories that the historian of cartography has to isolate the sub and maps-but Roman society offered a new educa stantial challenge to earlier theories and frequently their tional market for the cartographic knowledge codified reformulation in new maps. by the Greeks. Many influential Romans both in the In relation to the geography of Europe, the carto republic and in the early empire, from emperors down graphic material in the History of Polybius (ca. 200 to ward, were enthusiastic Philhellenes and were patrons post 118 B.C.) provides a first illustration of this ten of Greek philosophers and scholars. In the middle of the dency. Born at Megalopolis in the Peloponnese, Polybius second century B.C. the Scipionic circle, a group of prom had been active in the political and military life of inent Philhellenes, promoted the study of all things Greece. Taken to Rome as a hostage in 168 B.C., he also Greek; and when in 146 B.C. military rivalry from Car demonstrates by his career the importance of Roman thage and Greece was eliminated, Rome wielded the patronage in the continuation and spread of Greek car political power, but Greece provided the chief intellec tography, for he attracted the attention of L. Aemilius tual output within, and often on behalf of, Roman do Paullus and became a close friend of Scipio Aemilianus, minions. Throughout the second and first centuries B.C. who, besides giving him access to public records, took and beyond, it was thus men of Greek birth and edu Polybius with him on some of his campaigns to Spain cation-such as Polybius, Crates of Mallos, Hipparchus, and to North Africa. and Strabo-who continued to make fundamental con Polybius composed a History in forty books (of which tributions to the development of scientific mapping and the first five books are extant and the remainder are who provided a continuous link with these activities in known through Strabo and other sources) describing the the Hellenistic world and their culmination in the later prodigious rise of Rome in the fifty years between the syntheses of Claudius Ptolemy. Second Punic War and the battle of Pydna (218-168 161 162 Cartography in Ancient Europe and the Mediterranean B.C.).1 Conscious of the importance of a close critical map and put the northern limit of the inhabited world knowledge of the countries in which historical events at the parallel of Ierne (Ireland) (54°N), situated under took place, Polybius devoted part of his work to a geo the arctic circle containing the stars always visible from graphical description of Europe. Strabo tells us that mainland Greece and Rhodes (36°N).5 "Polybius, in his account of the geography of Europe, These criticisms by Polybius show the impact of says he passes over the ancient geographers but examines Eratosthenes' work and methods on the subsequent de the men who criticise them, namely, Dicaearchus, and velopment of cartography and mapping. In particular, Eratosthenes, who has written the most recent treatise the rigorous application of geometry had come to be on Geography; and Pytheas, by whom many have been considered essential for drawing maps to scale. Polybius misled.,,2 Strabo then gives us an example of such crit had applied these principles to Eratosthenes' map and icism, citing Dicaearchus's distances along the dia measurements when he undertook his description of Eu phragma (p. 152 above), and Polybius's use of rope and, as a result, probably drew a new map, with geometric arguments to prove them erroneous. Dicaear reduced latitudinal extent. chus, according to Polybius, had estimated the distance The continuing influence of Greek cartography, as between the Straits of Messina and the Straits of Gi reinterpreted by Greeks, within the new framework of braltar at 7,000 stades. This line can be considered the Roman society is also shown by references to the famous base of an obtuse-angled triangle with Narbo (Nar terrestrial globe of Crates of Mallos (fl. 150 B.C.), known bonne) as its apex (fig. 10.1). Polybius argued that one to us through Strabo.6 Although born at Mallos in Cil side of the obtuse angle, from the Straits of Messina to icia, Crates spent most of his life in Pergamum, as head Narbo, measured more than 11,200 stades, the other a of the newly established library, one of the institutions little less than 8,000. Since the perpendicular dropped to challenge the supremacy of Alexandria. He was in from Narbo to the base is 2,000 stades, "it is clear from 1. Polybius also took up Eratosthenes' idea that the regions near the principles of elementary geometry that the length of the equator had a more temperate climate than the ones near the the coast-line from the Strait [of Messina] to the Pillars tropics. Writing a book called The Inhabited World below the Equa [via Narbo; totals 19,200 stades] exceeds the length of tor, known to us through Geminus, Introduction to Phenomena, the straight line through the open sea by very nearly five Polybius applied the tenets of spherical geometry to this problem; see Geminus, Introduction aux phenomenes, ed. and trans. Germaine Au hundred stadia.,,3 Thus the distance from the Straits of jac (Paris: Belles Lettres, 1975), 16.32. The main argument in favor Messina to the Straits of Gibraltar along the diaphragma of Eratosthenes' hypothesis is that the sun, around the time of the is at least 18,700 stades instead of the 7,000 given by solstices, lingers for a long while over the tropics, burning the country, Dicaearchus.4 This brief example clearly shows the part but at the equinoxes it passes quickly over the equator. The basis for geometric reasoning played in Polybius's assessment of this interpretation is that in its annual apparent motion along the the map drawn by Dicaearchus. ecliptic, the sun, though moving at constant speed, appears to us to be almost motionless as it approaches and recedes from a tropic (the days, longer than those at the equator, are almost the same length for forty days). These conclusions are likely to have been illustrated by Narbo diagrams. For a general work on Polybius, see Frank William Wal 8,0 &ca es bank, A Historical Commentary on Polybius, 3 vols. (Oxford: Clar N- endon Press, 1957-79). Straits of 18,700 stades Straits of 2. Strabo Geography 2.4.1; see The Geography of Strabo, 8 vols., Gibraltar Messina trans. Horace Leonard]ones, Loeb Classical Library (Cambridge: Har FIG. 10.1. POLYBIUS'S ESTIMATE OF THE LENGTH OF vard University Press; London: William Heinemann, 1917-32). Also THE WESTERN MEDITERRANEAN. Whereas Dicaearchus see Strabo, Geographie, ed. Fran~ois Lasserre, Germaine Aujac, et al. stated a distance of 7,000 stades from the Straits of Gibraltar (Paris: Belles Lettres, 1966-). to the Straits of Messina, Polybius used basic geometry to show 3. Strabo Geography 2.4.2 (note 2). See also Walbank, Polybius, that it was, in fact, at least 18,700 stades. 1:371 (note 1). 4. The actual distance between the Straits of Messina and the Straits of Gibraltar is about 1,200 miles (1,930 kilometers). As for Europe in general, Polybius likewise severely 5.