Every country whose history we examine proves the recipient of successive streams of humanity. Even sea-girt England has received various intruding peoples from the Roman occupation to the recent influx of Russian Jews. In prehistoric times it combined several elements in its population, as the discovery of the "long barrow" men and "round barrow" men by archaeologists, and the identification of a surviving Iberian or Mediterranean strain by ethnologists go to prove.126 Egypt, Mesopotamia, and India tell the same story, whether in their recorded or unrecorded history. Tropical Africa lacks a history; but all that has been pieced together by ethnologists and anthropologists, in an effort to reconstruct its past, shows incessant movement,—growth, expansion and short-lived conquest, followed by shrinkage, expulsion or absorption by another invader.127 To this constant shifting of races and peoples the name of historical movement has been given, because it underlies most of written history, and constitutes the major part of unwritten history, especially that of savage and nomadic tribes. Two things are vital in the history of every people, its ethnic composition and the wars it wages in defense or extension of its boundaries. Both rest upon historical movements,—intrusions, whether peaceful or hostile, into its own land, and encroachments upon neighboring territory necessitated by growth. Back of all such movements is natural increase of population beyond local means of subsistence, and the development of the war spirit in the effort to secure more abundant subsistence either by raid or conquest of territory.

This movement is and has been universal and varied. When most unobtrusive in its operation, it has produced its greatest effects. To seize upon a few conspicuous migrations, like the Völkerwanderung and the irruption of the Turks into Europe, made dramatic by their relation to the declining empires of Rome and Constantinople, and to ignore the vast sum of lesser but more normal movements which by slow increments produce greater and more lasting results, leads to wrong conclusions both in ethnology and history. Here, as in geology, great effects do not necessarily presuppose vast forces, but rather the steady operation of small ones. It is often assumed that the world was peopled by a series of migrations; whereas everything indicates that humanity spread over the earth little by little, much as the imported gypsy moth is gradually occupying New England or the water hyacinth the rivers of Florida. Louis Agassiz observed in 1853 that "the boundaries within which the different natural combinations of animals are known to be circumscribed upon the surface of the earth, coincide with the natural range of distinct types of man."128 The close parallelism between Australian race and flora, Eskimo race and Arctic fauna, points to a similar manner of dispersion. Wallace, in describing how the Russian frontier of settlement slowly creeps forward along the Volga, encroaching upon the Finnish and Tartar areas, and permeating them with Slav blood and civilization, adds that this is probably the normal method of expansion.129 Thucydides describes the same process of encroachment, displacement, and migration in ancient Hellas.130 Strabo quotes Posidonius as saying that the emigration of the Cimbrians and other kindred tribes from their native seats was gradual and by no means sudden.131 The traditions of the Delaware Indians show their advance from their early home in central Canada southward to the Delaware River and Chesapeake Bay to have been a slow zigzag movement, interrupted by frequent long halts, leaving behind one laggard group here and sending out an offshoot there, who formed new tribes and thereby diversified the stock.132 It was an aimless wandering, without destination and purpose other than to find a pleasanter habitat. The Vandals appear first as "a loose aggregation of restless tribes who must not be too definitely assigned to any precise district on the map," somewhere in central or eastern Prussia.133 Far-reaching migrations aiming at a distant goal, like the Gothic and Hunnish conquests of Italy, demand both a geographical knowledge and an organization too high for primitive peoples, and therefore belong to a later period of development.134

The long list of recorded migrations has been supplemented by the researches of ethnologists, which have revealed a multitude of prehistoric movements. These are disclosed in greater number and range with successive investigation. The prehistoric wanderings of the Polynesians assume far more significance to-day than a hundred years ago, when their scope was supposed to have its western limit at Fiji and the Ellice group. They have now been traced to almost every island of Melanesia; vestiges of their influence have been detected in the languages of Australia, and the culture of the distant coasts of Alaska and British Columbia. The western pioneers of America knew the Shoshone Indians as small bands of savages, constantly moving about in search of food in the barren region west of the Rocky Mountains, and occasionally venturing eastward to hunt buffalo on the plains. Recent investigation has identified as offshoots of this retarded Shoshonean stock the sedentary agriculturalists of the Moqui Pueblo, and the advanced populations of ancient Mexico and Central America.135 Here was a great human current which through the centuries slowly drifted from the present frontier of Canada to the shores of Lake Nicaragua. Powell's map of the distribution of the linguistic stocks of American Indians is intelligible only in the light of constant mobility. Haebler's map of the South American stocks reveals the same restless past. This cartographical presentation of the facts, giving only the final results, suggests tribal excursions of the nature of migrations; but ethnologists see them as the sum total of countless small movements which are more or less part of the normal activity of an unrooted savage people. [Map page 101.]

Otis Mason finds that the life of a social group involves a variety of movements characterized by different ranges or scopes. I. The daily round from bed to bed. II. The annual round from year to year, like that of the Tunguse Orochon of Siberia who in pursuit of various fish and game change their residence within their territory from month to month, or the pastoral nomads who move with the seasons from pasture to pasture. III. Less systematic outside movements covering the tribal sphere of influence, such as journeys or voyages to remote hunting or fishing grounds, forays or piratical descents upon neighboring lands eventuating usually in conquest, expansion into border regions for occasional occupation or colonization. IV. Participation in streams of barter or commerce. V. And at a higher stage in the great currents of human intercourse, experience, and ideas, which finally compass the world.136 In all this series the narrower movement prepares for the broader, of which it constitutes at once an impulse and a part.

The real character and importance of these movements have been appreciated by broad-minded historians. Thucydides elucidates the conditions leading up to the Peloponnesian War by a description of the semi-migratory population of Hellas, the exposure of the more fertile districts to incursions, and the influence of these movements in differentiating Dorian from Ionian Greece.137 Johannes von Muller, in the introduction to his history of Switzerland, assigns to federations and migrations a conspicuous rôle in historical development. Edward A. Ross sees in such movements a thorough-going selective process which weeds out the unfit, or rather spares only the highly fit. He lays down the principle that repeated migrations tend to the creation of energetic races of men. He adds, "This principle may account for the fact that those branches of a race achieve the most brilliant success which have wandered the farthest from their ancestral home.... The Arabs and Moors that skirted Africa and won a home in far-away Spain, developed the most brilliant of the Saracen civilizations. Hebrews, Dorians, Quirites, Rajputs, Hovas were far invaders. No communities in classic times flourished like the cities of Asia created by the overflow from Greece. Nowhere under the Czar are there such vigorous, progressive communities as in Siberia."138 Brinton distinguishes the associative and dispersive elements in ethnography. The latter is favored by the physical adaptability of the human race to all climates and external conditions; it is stimulated by the food-quest, the pressure of foes, and the resultant restlessness of an unstable primitive society.139

The earth's surface is at once factor and basis in these movements. In an active way it directs them; but they in turn clothe the passive earth with a mantle of humanity. This mantle is of varied weave and thickness, showing here the simple pattern of a primitive society, there the intricate design of advanced civilization; here a closely woven or a gauzy texture, there disclosing a great rent where a rocky peak or the ice-wrapped poles protrude through the warm human covering. This is the magic web whereof man is at once woof and weaver, and the flying shuttle that never rests. Given a region, what is its living envelope, asks anthropo-geography. Whence and how did it get there? What is the material of warp and woof? Will new threads enter to vary the color and design? If so, from what source? Or will the local pattern repeat itself over and over with dull uniformity?

The checks to this native mobility of primitive peoples are two: physical and mental. In addition to the usual barriers of mountains, deserts, and seas before the invention of boats, primeval forests have always offered serious obstacles to man armed only with stone or bronze axe, and they rebuffed even man of the iron age. War and hunting parties had to move along the natural clearings of the rivers, the tracks of animals, or the few trails beaten out in time by the natives themselves. Primitive agriculture has never battled successfully against the phalanx of the trees. Forests balked the expansion of the Inca civilization on the rainy slope of the Andes, and in Central Africa the negro invaded only their edges for his yam fields and plantain groves. The earliest settlements in ancient Britain were confined to the natural clearings of the chalk downs and oolitic uplands; and here population was chiefly concentrated even at the close of the Roman occupation. Only gradually, as the valley woodlands were cleared, did the richer soil of the alluvial basins attract men from the high, poor ground where tillage required no preliminary work. But after four centuries of Roman rule and Roman roads, the clearings along the river valleys were still mere strips of culture mid an encompassing wilderness of woods. When the Germanic invaders came, they too appropriated the treeless downs and were blocked by the forests.140 On the other hand, grasslands and savannahs have developed the most mobile people whom we know, steppe hunters like the Sioux Indians and Patagonians. Thus while the forest dweller, confined to the highway of the stream, devised only canoe and dugout boat in various forms for purposes of transportation, steppe peoples of the Old World introduced the use of draft and pack animals, and invented the sledge and cart.

Where a population too great to be dislodged occupies the land, conquest results in the eventual absorption of the victors and their civilization by the native folk, as happened to the Lombards in Italy, the Vandals in Africa and the Normans in England. Where the invaders are markedly superior in culture though numerically weak, conquest results in the gradual permeation of the conquered with the religion, economic methods, language, and customs of the new-comers.141 The latter process, too, is always attended by some intermixture of blood, where no race repulsion exists, but this is small in comparison to the diffusion of civilization. This was the method by which Greek traders and colonists Hellenized the countries about the eastern Mediterranean, and spread their culture far back from the shores which their settlements had appropriated. In this way Saracen armies soon after the death of Mohammed Arabized the whole eastern and southern sides of the Mediterranean from Syria to Spain, and Arab merchants set the stamp of their language and religion on the coasts of East Africa as far as Moçambique. The handful of Spanish adventurers who came upon the relatively dense populations of Mexico and Peru left among them a civilization essentially European, but only a thin strain of Castilian blood. Thus the immigration of small bands of people sufficed to influence the culture of that big territory known as Latin America.

Nor is this all. A torrent that issues from its source in the mountains is not the river which reaches the sea. On its long journey from highland to lowland it receives now the milky waters of a glacier-fed stream, now a muddy tributary from agricultural lands, now the clear waters from a limestone plateau, while all the time its racing current bears a burden of soil torn from its own banks. Now it rests in a lake, where it lays down its weight of silt, then goes on, perhaps across an arid stretch where its water is sucked up by the thirsty air or diverted to irrigate fields of grain. So with those rivers of men which we call migrations. The ethnic stream may start comparatively pure, but it becomes mixed on the way. From time to time it leaves behind laggard elements which in turn make a new racial blend where they stop. Such were the six thousand Aduatici whom Cæsar found in Belgian Gaul. These were a detachment of the migrating Cimbri, left there in charge of surplus cattle and baggage while the main body went on to Italy.142

A migration rarely involves a single people even at the start. It becomes contagious either by example or by the subjection of several neighboring tribes to the same impelling force, by reason of which all start at or near the same time. We find the Cimbri and Teutons combined with Celts from the island of Batavia143 in the first Germanic invasion of the Roman Empire. Jutes, Saxons and Angles started in close succession for Britain, and the Saxon group included Frisians.144 An unavoidable concomitant of great migrations, especially those of nomads, is their tendency to sweep into the vortex of their movement any people whom they brush on the way. Both individuals and tribes are thus caught up by the current. The general convergence of the central German tribes towards the Danube frontier of the Roman Empire during the Marcomannic War drew in its train the Lombards from the lower Elbe down to the middle Danube and Theiss.145 The force of the Lombards invading Italy in 568 included twenty thousand Saxons from Swabia, Gepidae from the middle Danube, Bulgarians, Slavs from the Russian Ukraine, together with various tribes from the Alpine district of Noricum and the fluvial plains of Pannonia. Two centuries later the names of these non-Lombard tribes still survived in certain villages of Italy which had formed their centers.146 The army which Attila the Hun brought into Gaul was a motley crowd, comprising peoples of probable Slav origin from the Russian steppes, Teutonic Ostrogoths and Gepidae, and numerous German tribes, besides the Huns themselves. When this horde withdrew after the death of Attila, Gepidae and Ostrogoths settled along the middle Danube, and the Slavonic contingent along the Alpine courses of the Drave and Save Rivers.147 The Vandal migration which in 409 invaded Spain included the Turanian Alans and the German Suevi. The Alans found a temporary home in Portugal, which they later abandoned to join the Vandal invasion of North Africa, while the Suevi settled permanently in the northwestern mountains of Spain. The Vandals occupied in Spain two widely separated districts, one in the mountain region of Galicia next to the Suevi, and the other in the fertile valley of Andalusia in the south, while the northeastern part of the peninsula was occupied by intruding Visigoths.148 Add to these the original Iberian and Celtic stocks of the peninsula and the Roman strain previously introduced, and the various elements which have entered into the Spanish people become apparent.149

The absorption of foreign elements is not confined to large groups whose names come down in history, nor is the ensuing modification one of blood alone. Every land migration or expansion of a people passes by or through the territories of other peoples; by these it is inevitably influenced in point of civilization, and from them individuals are absorbed into the wandering throng by marriage or adoption, or a score of ways. This assimilation of blood and local culture is facilitated by the fact that the vast majority of historical movements are slow, a leisurely drift. Even the great Völkerwanderung, which history has shown us generally in the moment of swift, final descent upon the imperial city, in reality consisted of a succession of advances with long halts between. The Vandals, whose original seats were probably in central or eastern Prussia, drifted southward with the general movement of the German barbarians toward the borders of the Empire late in the second century, and, after the Marcomannic War (175 A.D.), settled in Dacia north of the lower Danube under the Roman sway. In 271 they were located on the middle Danube, and sixty years afterwards in Moravia. Later they settled for seventy years in Pannonia within the Empire, where they assimilated Roman civilization and adopted the Arian form of Christianity from their Gothic neighbors.150 In Spain, as we have seen, they occupied Galicia and Andalusia for a time before passing over into Africa in 429. Here was a migration lasting two centuries and a half, reaching from the Baltic to the southern shores of the Mediterranean, starting on the bleak sterile plains of the north amid barbarous neighbors, ending in the sunny grain fields and rich cities of Roman Africa. The picture which we get of the victorious Vandals parceling out the estates of Roman nobles, and, from the standpoint of their more liberal faith, profiting by the dissensions of the two Catholic sects of Africa, shows us a people greatly modified by their long sweep through the civilized outskirts of the Empire. So it was with the Lombards and Goths who invaded Italy.

Among primitive tribes, who move in smaller groups and must conform closely to the dictates of their environment, the modifying effects of people and land through which they pass are conspicuous. Ratzel describes the gradual withdrawal of a Hottentot people from western Cape Colony far into the arid interior before the advance of Kaffirs and Europeans by saying: "The stock and name of the Namaquas wandered northward, acquiring new elements, and in course of time filling the old mold with new contents."151 This is the typical result of such primitive movements. The migration of the Delaware Indians from an early home somewhere northwest of the Great Lakes to their historical habitat between the Hudson and Potomac Rivers was a slow progress, which somewhere brought them into contact with maize-growing tribes, and gave them their start in agriculture.152 The transit lands through which these great race journeys pass exercise a modifying effect chiefly through their culture and their peoples, less through their physical features and climate. For that the stay of the visitants is generally too brief.

Even early maritime migrants did not keep their strains pure. The untried navigator sailing from island to headland, hugging the coast and putting ashore for water, came into contact with the natives. Cross currents of migration can be traced in Polynesian waters, where certain islands are nodal points which have given and received of races and culture through centuries of movement. The original white population of Uruguay differed widely from that of the other Spanish republics of South America. Its nucleus was a large immigration of Canary Islanders. These were descendants of Spaniards and the native Guanches of the Canaries, mingled also with Norman, Flemish and Moorish blood.153 The Norse on their way to Iceland may have picked up a Celtic element in the islands north of Scotland; but from the Faroe group onward they found only empty Iceland and Greenland. This was an exceptional experience. Early navigation, owing to its limitations, purposely restricted itself to the known. Men voyaged where men had voyaged before and were to be found. Journeys into the untenanted parts of the world were rare. However, the probable eastward expansion of the Eskimo along the Arctic rim of North America belongs in this class, so that this northern folk has suffered no modification from contact with others, except where Alaska approaches Asia.

Every aggressive historical movement, whether bold migration or forcible extension of the home territory, involves displacement or passive movement of other peoples (except in those rare occupations of vacant lands), who in turn are forced to encroach upon the lands of others. These conditions involve war, which is an important form of the historical movement, contributing to new social contacts and fusion of racial stocks. Raids and piratical descents are often the preliminary of great historical movements. They first expand the geographical horizon, and end in permanent settlements, which involve finally considerable transfers of population, summoned to strengthen the position of the interloper. Such was the history of the Germanic invasions of Britain, the Scandinavian settlements on the shores of Iceland, Britain, and France, and the incursions of Saharan tribes into the Sudanese states. Among pastoral nomads war is the rule; the tribe, a mobilized nation, is always on a war footing with its neighbors. The scant supply of wells and pasturage, inadequate in the dry season, involves rivalry and conflict for their possession as agricultural lands do not. Failure of water or grass is followed by the decline of the herds, and then by marauding expeditions into the river valleys to supply the temporary want of food. When population increases beyond the limits of subsistence in the needy steppes, such raids become the rule and end in the conquest of the more favored lands, with resulting amalgamation of race and culture.154

The wars of savage and pastoral peoples affect the whole tribe. All the able-bodied men are combatants, and all the women and children constitute the spoils of war in case of defeat. This fact is important, since the purpose of primitive conflicts is to enslave and pillage, rather than to acquire land. The result is that a whole district may be laid waste, but when the devastators withdraw, it is gradually repopulated by bordering tribes, who make new ethnic combinations. After the destruction of the Eries by the Iroquois in 1655, Ohio was left practically uninhabited for a hundred and fifty years. Then the Iroquoian Wyandots extended their settlements into northwestern Ohio from their base in southern Michigan, while the Miami Confederacy along the southern shore of Lake Michigan pushed their borders into the western part. The Muskingum Valley in the eastern portion was occupied about 1750 by Delawares from eastern Pennsylvania, the Scioto by Shawnees, and the northeast corner of the territory by detachments of Iroquois, chiefly Senecas.155 The long wars between the Algonquin Indians of the north and the Appalachian tribes of the south kept the district of Kentucky a No Man's Land, in convenient vacancy for occupation by the white settlers, when they began the westward movement.156 [Map page 156.]

This desolation is produced partly by killing, but chiefly by enslavement of prisoners and the flight of the conquered. Both constitute compulsory migrations of far-reaching effect in the fusion of races and the blending of civilizations. The thousands of Greek slaves who were brought to ancient Rome contributed to its refinement and polish. All the nations of the known world, from Briton to Syrian and Jew, were represented in the slave markets of the imperial capital, and contributed their elements to the final composition of the Roman people. When we read of ninety-seven thousand Hebrews whom Titus sold into bondage after the fall of Jerusalem, of forty thousand Greeks sold by Lucullus after one victory, and the auction sub corona of whole tribes in Gaul by Cæsar, the scale of this forcible transfer becomes apparent, and its power as an agent of race amalgamation. Senator Sam Houston of Texas, speaking of the Comanche Indians, in the United States Senate, December 31, 1854, said: "There are not less than two thousand prisoners (whites) in the hands of the Comanches, four hundred in one band in my own state.... They take no prisoners but women and boys."157 It was customary among the Indians to use captured women as concubines and to adopt into the tribe such boys as survived the cruel treatment to which they were subjected. Since the Comanches in 1847 were variously estimated to number from nine to twelve thousand,158 so large a proportion of captives would modify the native stock.

In Africa slavery has been intimately associated with agriculture as a source of wealth, and therefore has lent motive to intertribal wars. Captives were enslaved and then gradually absorbed into the tribe of their masters. Thus war and slavery contributed greatly to that widespread blending of races which characterizes negro Africa. Slaves became a medium of exchange and an article of commerce with other continents. The negro slave trade had its chief importance in the eyes of ethnologists and historians because, in distributing the black races in white continents, it has given a "negro question" to the United States, superseded the native Indian stock of the Antilles by negroes, and left a broad negro strain in the blood of Colombia, Venezuela, and Brazil. This particular historical movement, which during the two centuries of its greatest activity involved larger numbers than the Tartar invasion of Russia or the Turkish invasion of Europe, for a long period gave to black Africa the only historical importance which it possessed for the rest of the world.159

In higher stages of political development, war aiming at the subjugation of large territories finds another means to fuse the subject peoples and assimilate them to a common standard of civilization. The purpose is unification and the obliteration of local differences. These are also the unconscious ends of evolution by historical movement. With this object, conquerors the world over have used a system of tribal and racial exchanges. It was the policy of the Incas of ancient Peru to remove conquered tribes to distant parts of the realm, and supply their places with colonists from other districts who had long been subjected and were more or less assimilated.160 In 722 B.C. the Assyrian king, Sargon, overran Samaria, carried away the Ten Tribes of Israel beyond the Tigris and scattered them among the cities of Media, where they probably merged with the local population. To the country left vacant by their wholesale deportation he transplanted people from Babylon and other Mesopotamian cities.161 The descendants of these, mingled with the poorer class of Jews still left there, formed the despised Samaritans of the time of Christ. The Kingdom of Judah later was despoiled by Nebuchadnezzar of much of its population, which was carried off to Babylon.

This plan of partial deportation and colonization characterized the Roman method of Romanization. Removal of the conquered from their native environment facilitated the process, while it weakened the spirit and power of revolt. The Romans met bitter opposition from the mountain tribes when trying to open up the northern passes of the Apennines. Consequently they removed the Ligurian tribe of the Apuanians, forty-seven thousand in number, far south to Samnium. When in 15 B.C. the region of the Rhaetian Alps was joined to the Empire, forty thousand of the inhabitants were transplanted from the mountains to the plain. The same method was used with the Scordisci and Dacians of the Danube. More often the mortality of war so thinned the population, that the settlement of Roman military colonies among them sufficed to keep down revolt and to Romanize the surviving fragment. The large area of Romance speech found in Roumania and eastern Hungary, despite the controversy about its origin,162 seems to have had its chief source in the extensive Roman colonies planted by the Emperor Trajan in conquered Dacia.163 In Iberian Spain, which bitterly resisted Romanization, the process was facilitated by the presence of large garrisons of soldiers. Between 196 and 169 B.C. the troops amounted to one hundred and fifty thousand, and many of them remained in the country as colonists.164 Compare the settlement of Scotch troops in French Canada by land grants after 1763, resulting in the survival to-day of sandy hair, blue eyes, and highland names among the French-speaking habitants of Murray Bay and other districts. The Turks in the fifteenth century brought large bodies of Moslem converts from Asia Minor to garrison Macedonia and Thessaly, thereby robbing the Anatolian Plateau of half its original population. Into the vacuum thus formed a current of nomads from inner Asia has poured ever since.165