History of Geography

by Sir John Scott Keltie; O. J. R. Howarth

An important episode in the progress of a more accurate knowledge of the world of the Greeks was the Retreat of the Ten Thousand under Xenophon in 401–400 B.C. The younger Cyrus had made a great expedition from Sardis, in western Asia Minor, eastwards through the Cilician Gates to the Euphrates, and along the course of that river to the neighbourhood of Babylon. He was accompanied by a band of Greek mercenaries, who, after his defeat at Cunaxa, began the retreat of which Xenophon left a graphic account, containing what must have been to the Greeks much new information concerning the region from the junction of the Tigris and Euphrates northwards past Lake Van and through the mountains of Armenia, north and west to the shores of the Black Sea at Trapezus (Trebizond), and along the south coast of the Black Sea, partly by sea and partly by water, to Byzantium. Xenophon’s story is an illustration of the well-known fact that war is one of the chief means of promoting geographical knowledge. This will appear more clearly in the next important episode in the story of exploration—the campaign of Alexander the Great.

In the interval there were one or two writers from whose work something is to be gathered of Greek geographical knowledge and theory about the middle of the fourth century. The philosopher Plato (427–347 B.C.) may be referred to here in connection with his story, based on an Egyptian tradition, of the great island of Atlantis, that land which plays so important a part in later mythical geography. In the Egyptian story it lay just beyond the Pillars of Hercules, and adjacent to it was an archipelago. This would aid its later identification with the Canaries, though it came also to be connected with America and other known lands besides, as well as giving name to an island in the Atlantic Ocean, the disproof of whose existence may almost be called modern. From Plato’s account of Atlantis as the home of a powerful people who in early times invaded the Mediterranean lands, it has also been sought to associate the tradition with Crete at the period of the Ægean civilization mentioned in the first chapter.

Some fragments exist of the writings of the historian Ephorus of Cyme in Æolis (c. 400–330 B.C.). He seems to have endeavoured to cover the whole field of the world as known to the Greeks, and conceived the four most distant regions of the earth to be occupied on the east by Indians, on the south by Ethiopians, on the north by Scythians, and on the west by Celts. The last he considered as occupying all Spain, as well as Gaul. Strabo (p. 24) commended his geographical work and his skill in separating myth from history. A document of this period is the Periplus, already referred to as known under the name of Scylax. This class of work became more and more common as navigation developed, and corresponded in some measure to the modern Admiralty guide or pilot. The Periplus is confined mostly to the regions known to the Greeks bordering the Mediterranean. From the Pillars of Hercules the writer follows the north coast eastwards, including the Adriatic and the Euxine as far as the mouth of the Tanais, which he regards as the continental boundary. He then follows the Levantine coast, the north African coast westward, and the west African coast as far as the island of Cerne. He incidentally makes what is regarded as the earliest extant mention of Rome; but his notions of rivers and other features away from the coast are generally erroneous.

Aristotle (384–322 B.C.), in two of his extant works, the Meteorologica and the treatise on the Heavens, revealed something of his ideas on physical geography and the figure of the earth and its relations to the heavenly bodies. He believed the earth to be a sphere in the centre of the universe, because that was a form which matter gravitating towards a centre would necessarily assume, also because the shadow cast by the earth on the moon during an eclipse is circular. He accepted the conclusion that the circumference of the earth was 400,000 stadia (nearly 46,000 miles). His views with reference to the cosmical relations of the earth were the same as those adopted by Eudoxus of Cnidus (fl. middle fourth century), but he did his best to prove them. He adopted, however, the prevalent view that the habitable world was confined to the temperate zone between the tropics and the arctic regions. He believed there must be a temperate zone in the southern hemisphere, though he did not suggest that it must be inhabited. In the Meteorologica he treats of such subjects as weather, rain, hail, earthquakes, etc., and their causes. He recognized that changes took place in the relations of land and sea. His knowledge of the origin and course of rivers and their relation to mountain systems was confused, and mainly erroneous; and it would seem that little progress had been made in geographical knowledge since the time of Herodotus. In the work of Aristotle’s successor, Theophrastus of Lesbos (c. 372–287), an important department of geographical study—that of distribution—finds a place in its particular application to plants.

Alexander the Great (356–323 B.C.), King of Macedon, however, during the last few years of his life, made possible by his campaigns a greater extension of Greek geographical knowledge than had taken place almost since Homeric times. When he passed eastward through Mesopotamia, by Babylon, Susa, and Persepolis, and through Media to the southern shore of the Caspian Sea, he was in a region which, though an ancient cradle of civilization, had been till then only vaguely known to the Greeks. Beyond that he entered new country, peopled by Herodotus and others with dubious tribal names. He came almost into the heart of Central Asia, founding a city on the upper course of the Jaxartes. Passing southwards through Bactria and across formidable ranges of mountains such as the Hindu Kush, he struck the upper course of the Indus, made his way down to its delta, and would have proceeded right into the heart of India and followed the Ganges to its mouth but for his mutinous troops. He returned through the north of Baluchistan and Persia to Ecbatana, and so homeward. He also sent a member of his staff, Nearchus, by sea along the coast of Baluchistan and Persia, in order to define it and to ascertain the extent of the Persian Gulf. Dicæarchus of Messana, a pupil of Aristotle, who died early in the third century B.C., used the geographical results of Alexander’s expeditions, including the distances obtained by his bematists, or measurers by pacing. Dicæarchus wrote a topography of Greece, and also drew on a map a parallel or equator, for the first time, so far as is known, along the length of the Mediterranean and, with a distorted idea of their relative directions, along the Taurus and Himalayan ranges. Before his time, and probably contemporaneously with Alexander’s campaigns, Pytheas of Massilia (Marseilles) visited (practically discovered) Britain, and made mention of Thule, six days’ voyage north of it, having perhaps heard of the Orkneys and Shetlands. As these islands, however, are at no such great distance as is here suggested from the nearest point of Britain, the name of Thule has been variously taken to represent some part of Norway, the Faeröe, or Iceland: it certainly seems by some later writers to be applied to Scandinavia, and in literary usage came to signify the uttermost north. Pytheas also obtained an idea of the Baltic Sea, and is considered by some to have entered it; he is stated to have reached the River Tanais; but if that is to be considered as one of the north European rivers, and not the known Tanais of the Black Sea basin, its identity is doubtful. Pytheas was a trained astronomer; he was one of the first to calculate latitudes, and had that of Massilia nearly correct; he heard of the unbroken summer daylight and winter darkness of the far north, and he noted various features of geographical interest, such as the decrease in the number of different grain crops observed as he travelled northward. He appears, in fact, from the references in other authors, which alone furnish us with knowledge of his work, in the light of a scientific traveller of a type rare in his time.

Mathematical geography was carried a long step forward by Eratosthenes (c. 276–194 B.C.), a native of Cyrene, who became chief librarian at Alexandria under Ptolemy III Euergetes. He calculated the circumference of the earth. He considered Syene to be situated on the tropic (which it was not, precisely), because at noon on the day of the summer solstice the sun appeared to shine directly down a deep well there. He therefore observed the zenith distance of the sun at Alexandria at the same time, and obtained his result from this and the measured distance between Alexandria and Syene. His result was to make the earth’s circumference only about one-seventh greater than it actually is. He also estimated the size of the habitable earth (œcumene), and considered it, as a result, to be about double as long from west to east as it was broad from north to south. But his estimate of the distance from what is now the extremity of Brittany to the known eastern limit of India was about one-third too great. On a map of the world he drew seven parallels, using the few points of which the latitudes had been worked out, and also seven meridians at irregular distances apart. Hipparchus (middle and second half of the second century), an astronomer, native of Nicæa in Bithynia, who worked in Rhodes, drew an elaborate series of parallels, and made the division into 360 degrees; the spaces between the lines he called climata, or zones. The problem presented by meridians was more difficult, for there was no instrument for the calculation of longitude like the gnomon for that of latitude. A well-recognised line was that taken to lie from the mouth of the Danube to that of the Nile—Herodotus had used this—and southward up the latter river; but not only the line itself, but also the ideas of intermediate points lying on it, were rather far from the truth.

Eratosthenes in his writings also dealt with the history of geography and with physical geography. This last branch attracted a number of students about this period and later, as, for example, Agartharchides or Agatharchus of Cnidus (middle of the second century B.C.). Crates of Mallus, in the first half of the same century, expressed the view of the Stoic philosophers that the spherical earth was divided into four inhabited quarters—the Œcumene (the known world), the Antipodes, the Periœci, and the Antœci. Posidonius the Stoic (c. 130–50 B.C.), among his studies in various departments of knowledge, included such subjects as the ocean, volcanoes, and earthquakes; he observed the interaction of the sun and moon in their influence on tides. He recalculated the circumference of the earth, but obtained an underestimate considerably further from the truth than Eratosthenes’s overestimate; and, owing to his high scientific reputation, his error persisted in much later work. Posidonius, before settling at Rhodes, had travelled widely in Africa, Spain, and western Europe generally; and both he and Agartharchides, like other writers of this period, and Aristotle before them, recognized the importance of the human side of geography, and the influence of physical environment on the political and social régime. Polybius (c. 204–122 B.C.) of Megalopolis in Arcadia, historian, statesman, and military commander, was inspired by extensive travel to introduce the results of topographical and geographical studies throughout his history. Among travellers who rank more nearly among explorers there may be mentioned at this period Eudoxus of Cyzicus (fl. c. 130 B.C.), who went on a trading expedition to India, in command of a fleet which was despatched by Ptolemy Euergetes of Egypt with the specific object of exploring the Arabian Sea. Eudoxus subsequently tried without success to circumnavigate Africa, making at least two voyages along the east coast. Finally, it must be remembered that at this period the extension of the knowledge of the world was mainly due no longer to Greek, but to Roman, activities, and Roman conquests were pushed beyond the confines of accurate Greek knowledge in various directions. Much geographical material was made available by writers on Roman military expeditions. Thus Pompey was accompanied in the Caucasian region by Theophanes of Mytilene, as historian of his campaigns; Julius Cæsar wrote his own account of lands into which he carried his arms (Gaul, etc.).

From all this it appears that, according to the lights of knowledge at the time, a fair conception existed of geographical study along the main lines which it follows to-day. There was therefore occasion for a general review of the whole subject; and this occasion was seized by Strabo, a native of Amasia in Pontus, who was born c. 63 B.C., and died in the second or third decade of the following century. He was educated partly at Rome, but his language and outlook were Greek. He travelled much, as far as Etruria, the Black Sea, and the borders of Ethiopia, as well as in Asia Minor, though he knew comparatively little of Greece. His geography, which was not finally completed till towards the close of his life, was the first attempt at covering the whole geographical field—mathematical, physical, and human—and his range was thus wider than that of Eratosthenes. Strabo used the recent Roman authorities to some extent, such as Cæsar’s Commentaries (in part) and a map of the Roman Empire by M. Vipsanius Agrippa, son-in-law of Augustus, which was set up in Rome; and he also preferred the authority of Polybius to that of Pytheas, but his sources were mostly Greek. His appreciation of them was not always wise. He ranked the Homeric poems highly, but discredited Herodotus, who on some points had better information than he. He added nothing to the mathematical branch, in which Eratosthenes was his master. He thus accepted the spherical form of the earth, its dimensions as laid down by his predecessors, and its division into five zones. He recognized Hipparchus’s view that further astronomical observations were essential to precision in earth-measurement and the position of points on the surface; but it was outside his province to add to those existing. His work in the physical field, however, improved upon that of his predecessors, and his surveys of the features and products of the various lands must have been singularly valuable for reference. The apportionment of the seventeen books of his geography is not without interest as a rough guide to the distribution of available material and to the author’s outlook. He devoted two books to introductory matter, to Spain and France two, to Italy two, to northern and eastern Europe one, to Greece and adjacent lands three, to the main divisions and remoter parts of Asia one, to Asia Minor three, to India and Persia one, to Syria and Arabia one, to Egypt and the rest of Africa one.

Rome did not carry on the Greek tradition of the study of geographical theory. H. F. Tozer, quoting J. Partsch, writes: “It has been aptly remarked that the task which Eratosthenes set himself of measuring the earth by means of the heavenly bodies, and that of Agrippa, who measured the Roman provinces by milestones, may be taken as typical of the genius of the two nationalities respectively.” Thus Pomponius Mela, purporting to survey the world in his De Chorographia (written c. 50 A.D.), followed the coast and described various countries in passing, but by no means all, and added very little to geographical knowledge at large. Pliny the Elder (c. 23–79) devoted three books and part of another of his Historia Naturalis to geography; but his geography may (at least in considerable part) be compared with the arid text-book of a generation ago, though in some instances his descriptions (as of features in Palestine, Syria, and Armenia) are valuable. As bearing on the quotation made above, it may be said here that the famous Roman system of road building gave rise to two classes of road-books (as they may be termed), one consisting of lists of stations and distances, such as the Antonine Itinerary (probably, in its original form, of the late third or fourth century), the other diagrammatic, such as the Peutinger Table (probably of the first half of the third century, though named after a scholar of the sixteenth), on which roads, stations, and other details were presented in a map-like form, but independently of true scale or direction. The Roman agrimensores were skilled surveyors.

It is not, then, surprising that the two great theoretical geographers next to be considered are not associated with the capital of the Roman Empire. Of the work of Marinus of Tyre nothing is known beyond what is recorded by his immediate successor, Ptolemy, who used and acknowledged his results—as far as concerned the Mediterranean fully, and in respect of other countries to a modified extent. Ptolemy, mathematician, astronomer, and geographer, was a native of Egypt, who worked at or in the neighbourhood of Alexandria in the second century. His geographical book was called Geographike Syntaxis. He carried mathematical geography far beyond the standard of his predecessors. He used the theoretical division of the globe into five zones by the equator and the tropics, adopted Hipparchus’s division of the equator into 360 degrees, and worked out a network of parallels of latitude and meridians of longitude, first thus applying these terms in their technical sense. In mapping the habitable world he used the Fortunate Isles, beyond the western confines of Europe and Africa, as the location of his prime meridian. The errors which resulted from the vague idea as to the position of these islands (the Canaries and Madeira), and from the fact that Ptolemy followed Posidonius’s underestimate of the circumference of the globe and made his degree at the equator equal to 500 instead of 600 stadia,[2] have been very fully analysed, but cannot be even summarized here.