From this point it becomes necessary to vary the treatment of our subject hitherto followed. With the breakup of the Roman Empire and the establishment of Christianity the old learning was obliterated. Religion became the central fact of intellectual exercise, and, except in so far as Christian doctrine and Holy Scripture involved reference to natural phenomena, every branch of natural science was withered by the breath of theology. The first serious assaults of the barbarian invader were made on the frontiers of the Roman Empire in the fourth century A.D.; in 330 the seat of government was transferred from Rome to Byzantium, and at the close of the century the empire was divided into eastern and western parts. It has often been pointed out that these events did more than mark the beginning of the disruption of the Roman Empire; they also mark the parting of the ways of eastern and western European religion and culture. In the west it became the function of Christianity to teach and civilize peoples untaught and uncivilized; but, limited and intolerant as was its outlook upon natural science generally, it discarded the learning of the pre-Christian era. We have now to inquire how geography was affected by this attitude towards secular learning.

It is true that the habit of travel, so far from being forgotten, was even fostered by missionary work and34 the practice of pilgrimage. Again, opportunities for the extension of geographical knowledge were provided by various episodes in the history of the centuries with which we are now concerned; thus Procopius, the historian of the Persian, Vandal, and Gothic wars of the epoch of the Roman (Byzantine) emperor Justinian in the sixth century, had ample opportunities for geographical description and used them well. Justinian even despatched an expedition to China (which returned thence). But the geographical theorists of the period now under review had little if any concern with contemporary travellers’ results.

The Christian cosmographers, having found in a spiritual sense a new heaven and a new earth, were at pains to create them in a scientific sense also. It was their aim to reconcile geographical theory with the literal sense of Holy Scripture, and they were not only unable to explain, but were (for the most part) willing to disprove, pre-Christian theory by that light. Thus Lactantius Firmianus (c. 260–340), becoming converted, denied the possibility of the sphericity of the earth or the existence of antipodes. On the other hand, this conception died hard, for it was maintained by pagan writers at this time—as, for instance, Martianus Capella, who, writing in the third or fourth century, followed such authorities as Ptolemy and Pythagoras. And these pre-Christian views must have caused some of the Christian authors to doubt, for they left unsettled such questions as that of the earth’s shape, on the plea that they formed no part of the Christian doctrine; an instance of this attitude is provided by St. Basil the Great of C?sarea (c. 330–379) in his treatise on the Hexaemeron (Six Days of the Creation).
Fig. 5.—The World according to Cosmas Indicopleustes.

One of the principal popular attractions of geography35 has always been its function of describing the wonders of distant lands, and in Julius Solinus Polyhistor (probably of the third century) we have a typical geographer of the marvellous, who in his Collectanea Rerum Memorabilium drew upon Pliny, Pomponius Mela, and many earlier authors for a description of the wonders of the world, and became himself regarded as a high authority. With such influences at work on the study of geography, the genesis of the theories of Cosmas Indicopleustes becomes perhaps less surprising than the theories themselves. He was a merchant of Alexandria, and a traveller (as his surname is inaccurately intended to record) in the Red Sea and the ocean beyond, who, thus fortified in geographical study, became a monk and wrote his Christian Topography about the middle of the sixth century, in opposition to36 the pre-Christian theories. Under his pen the inhabited earth became a flat, rectangular oblong surrounded by oceans. At the north is a conical mountain round which the sun (which is some forty miles in diameter and at no great distance from the earth) revolves, passing about the summit in summer, so that it is hidden from the earth for a shorter time daily than in the winter, when it passes about the base. Again, in such conditions as have been indicated, it is at least intelligible that a responsible writer should accept a mountain 250 miles high, as is stated of Mount Pelion by Dicuil, an Irish monastic scholar who completed his De Mensura Orbis Terr? in 825. He, however, was little else than a compiler, and in the manner of his kind made an ill choice of sources. Among them, however, he refers to surveys made by Julius C?sar, Augustus, and one of the emperors Theodosius; the originals thus referred to are unknown. To mention the various Churchmen and others who, though in no sense geographers, were expected to deal with the theories of the earth and the universe in connection with their religious doctrines, would make but a tedious list.

The view of the sphericity of the earth was not wholly lost. Certain expressions of the Venerable Bede (c. 672–735), even if he did not specifically formulate the theory, were capable of that construction, although in 741 we find Virgilius, the Irish bishop of Salzburg, attacked by the Pope for his assertion of the existence of antipodes (or at least an assertion that may bear that construction). Nevertheless, these theories made headway, and from the eleventh century they became more and more acceptable to leaders of learning. Adam of Bremen accepted them; he is also an important37 figure in other departments of geography. He flourished in the second half of the eleventh century; his history is a specially valuable authority for the Baltic lands and other parts of Scandinavia and Russia. Its fourth book is a Descriptio Insularum Aquilonis, for which there was no little material, for not only had holy men from Ireland visited the Orkneys, Shetlands, Faer?e, and Iceland in the sixth and seventh centuries, but the Norsemen had entered upon their period of colonizing activity; besides Great Britain and Ireland they had reached Iceland in 874, Greenland a century later, and Vinland in 1000; and this last, that much-debated3 landfall situated somewhere on the North American coast south-west of Greenland, is first mentioned by Adam of Bremen. A similar appreciation of north European geography had been shown by King Alfred the Great, who in translating (and freely editing) earlier works had introduced much of the knowledge acquired down to his own time.

3 Not only so in modern times; at least one Scandinavian geographer, of the end of the thirteenth century, was prepared to recognize it as belonging to Africa.
Fig. 6.—Beatus’s Map.

Monastic cartography did not keep pace with theory. The disputed habitable land beyond the confines of the known world, and separated from it by the impassable torrid zone (a classical conception), appeared in maps of the seventh and eighth centuries. Apart from this (and it came to be generally admitted) we have rectangular oblong maps like that of Cosmas, and circular maps, out of which was evolved the diagrammatic form of a T within an O, where the T represented the Mediterranean, the Tanais, and the Nile, its upright showing the westward extension of the sea, and the cross-stroke the two rivers, to left and right39 respectively, so that the west was at the bottom of the map. Europe lay within the left-hand angle of the T, Africa in the right-hand angle; Asia was the half circle above it. The holy city of Jerusalem lay “in the midst of the nations.” Some maps, again, gave the earth an oval form. In all, the habitable earth was still surrounded by ocean. In the far east sometimes appeared Paradise. This feature and the unknown habitable world above mentioned were both shown in the map of Beatus, a Spanish priest (c. 730–798), who illustrated his Commentaria in Apocalypsin with one of the earliest known Christian maps of the world, several copies of which, dating from the tenth to the thirteenth centuries, are preserved. In this map the “known” habitable world appears as a dome-shaped mass with its flat base to the south, forming the northern shore of a strait separating it from the unknown southern land. The known world is broken for more than half its breadth by the vast gulf of the Mediterranean, which has two great arms reaching far northward; the Caspian Sea is a gulf opening into the north-east part of the circumfluent ocean, in which are set islands in an orderly ring all round the world; all sense of direction in the flow of rivers is awry, and topographical accuracy is, of course, entirely wanting.

What early Christianity lost by looking askance at classical theory the Arabs, after the establishment of Muhammadan power in the seventh century, in great measure gained, for they were free of scruple as regarded the earlier learning, and eager for knowledge. Early in the ninth century the Caliph Al-Mamun of Bagdad gave a strong impulse to geographical and kindred studies. He caused translations to be made of Ptolemy’s astronomical and geographical works,40 and of those of other ancient authorities, among whom was Marinus of Tyre. Muhammad ben Musa, librarian of Bagdad, compiled a Description of the World, or gazetteer of place-names with their positions, on the Ptolemaic model. Degrees were measured in Syria and Mesopotamia. Among Arab descriptive works the first which survives is that of Suleiman, a merchant, who made voyages to India and China in the middle of the ninth century. In the first half of the following century Masudi travelled widely—to India and Ceylon, probably to China, to Madagascar, to the Caspian, and in Syria and Egypt. His work, the Meadows of Gold and Mines of Precious Stones, is an example of the application of the results of travel and personal observation to history; he was commonly compared with Pliny. The Muhammadan demand for geographical works at this period appears to have been great, from the fact that Abu Zaid’s work, written about 921, was revised thirty years later by Istakhri, who travelled all through the Muhammadan lands, in his Book of Climates (or Zones); and this was again revised and extended by Ibn Haukal in 977 in his Book of Roads and Kingdoms.

A more important figure is Idrisi (c. 1099–1154), an Arab of Spanish birth, who was probably educated at the great centre of learning, Cordova. He travelled in North Africa and Asia Minor, and, settling in Sicily, made a celestial sphere and a map of the world in silver for King Roger II. Idrisi conceived a substitute for a projection by dividing the inhabited world into seven climates or zones between the equatorial line and the arctic region; each of these was divided into eleven equal parts by perpendicular lines. The squares thus formed were used (to the disregard of natural or41 political divisions) in a description of the earth carried out by Idrisi for the king, which is noteworthy as having been put together, at least in part, from the reports of an organized system of observers, who were despatched at Roger’s order to various countries. Arabian cartography, however, so far as is known, was primitive. Yet the Arab astronomers made some close meridianal determinations—an error of only three degrees between Toledo and Bagdad, for example, and a calculation of the major axis of the Mediterranean which was very near the truth.

Before leaving this period it is worth remarking how commercial activity had not only developed within, but had circumscribed the European area. The Arabs, penetrating eastward into Asia, came in contact with traders from north and western Europe using a route which, from the eighth century, passed “from India through Novgorod to the Baltic; and Arab coins found in Sweden prove how closely the enterprise of the Arabs and the Northmen intertwined” (H. R. Mill). Thus ways were prepared for the advancement of geographical knowledge when the science should emerge from its stagnation.