Ptolemy’s work on physical features was on the whole poor, and he neglected the human side of geography. Discarding the idea of the circumfluent ocean, he supposed the extension of unknown lands northward in Europe, eastward in Asia, and southward in Africa, beyond the limits in which he attempted to portray their outlines; and he even suggested a land connection between south-eastern Asia and southern Africa. Before his time the precision of mathematical method had far surpassed that of the topographical material to which it was applied.
Pausanias, a Greek probably of Lydia and about contemporary with Ptolemy, wrote a description (Periegesis) of Greece, which, apart from the archæological value which is its chief interest, contains references to various phenomena of physical geography, while as a detailed topographical work it stands alone in the literature of which an outline has thus far been given.
Chapter III.
THE DARK AGE
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 and 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 Cæsarea (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 geography 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 to 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 Terræ 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 Cæsar, 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.