(4) There are the Bulgars, originally a Tartar people coming from the banks of the Volga, who entered Bulgaria in the seventh century as the Normans entered England at a later date, and who mingled with a Slav race they found there--at first as conquerors, afterwards becoming the absorbed race. (5) There are the Serbs, somewhat akin to the Bulgars, whose original home seems to have been that of the Don Cossacks, who also came into the Peninsula in the seventh century. They are of purer Slav blood than the Bulgars. (6) There are the Montenegrins, an off-shoot of the Serbs, who in the fourteenth century, when the Servian Empire fell, took to the hills and maintained their independence. Those are the six main racial elements. But there are other scraps of peoples--the Albanians, for example, and the Macedonians, and tribes of Moslem Bulgars, and some Asiatic elements brought in by the Turks. So far, then, the answer to the question, "Why are the Balkans so often at war?" is easy of answer. Given the existence on one peninsula of six different races, four of which have past great traditions of Empire, and there is certain to be uneasy house-keeping. But the inquiry has to be pushed further. Why is it that this unhappy Peninsula should have been made thus a scrap-heap for bits of nations, a refuge for sore-headed remnants of Imperial peoples? The answer to that is chiefly geographical. A study of the map will show that when there was a great movement from the north of Europe to the south, its easiest line of march was down the valley of the Danube along the Balkan Peninsula. In prehistoric times the peoples around the European shores of the Mediterranean brought to accomplishment a very advanced type of civilisation. It owed its foundations to Egypt or to the Semitic peoples, such as the Phoenicians, the Tyrians, and the Carthaginians, whose race-home was Asia Minor. Whilst this Mediterranean civilisation was being shaped in the south--in the north, in the forests or plains along the shores of the Baltic and of the North Sea, the fecund Teutonic people were swelling to a mighty host and overflowing their boundaries. A flood of these people in time came surging south searching for new lands. The natural course of that flood was by the valley of the Danube to the Balkan Peninsula. Down that peninsula they cut their path--not without bloodshed one may guess--and founded the Grecian civilisation. Of this prehistoric movement there is no written evidence; but it is accepted by anthropologists as certain. Thus Sir Harry Johnston records, not as a surmise but as a fact: The Nordic races, armed with iron or steel swords, spears and arrow-heads, descended on the Alpine, Iberian, Lydian, and Aegean peoples of Southern Europe with irresistible strength. It was iron against bronze, copper, and stone; and iron won the day.