It is a remarkable ethnological fact, and one for which there does not seem any obvious explanation, that, almost ever since the great barbarian migrations of the fourth century, the country between the Danube and the Carpathian mountains has been occupied by a people belonging to that which, for want of a better word, we call the Turanian stock; and yet that this Turanian deposit should not have been one and the same throughout, but was the result of three distinct migrations. In the fourth century the great non-Aryan nation on the Middle Danube was the Huns; from the tenth century to the present day it has been that noble nation whom their Sclavonic neighbors have named Hungarians, but who call themselves Magyars; between 567 and 800, it was the savage and somewhat uninteresting people of the Avars.[51] The power of the Avars was at its height in the reign of the emperor Heraclius (626) when they formed the siege of Constantinople, and, joining hands with the Persians, had well-nigh accomplished the ruin of the eastern Empire. Soon after this came the revolt of the Bulgarians from the Avar sway, and from that time onward, the power of the Avars steadily declined, but though no longer formidable to Constantinople they were still securely quartered in the vast plains of Hungary, and were most unwelcome neighbors to their old allies the Lombards of Italy. Twice in the course of the seventh century had they descended upon the duchy of Friuli, and each time their invasions had been marked by that character of destruction and purposeless brutality which has ever been the especial note of the Tartar conqueror. If the Avars were at all like their Hunnish kinsmen (which is not improbable) they were small of stature, and swarthy in color. Their long locks hanging down behind, in a kind of woven pigtails, are specially noticed by the Frankish poets. They were essentially a predatory nation, and (again arguing from the analogy of the Huns) we may presume that they were a nation of horsemen, dashing hither and thither on their nimble and hardy ponies, and vanishing ere the heavy squadrons of the Greeks or the Lombards could come up with them. They had one chief ruler, who was called the _chagan_ of the Avars--the same title with which we are familiar as the Tartar khan--and under him, in a degree of subordination which it would be hopeless now to determine, were lieutenants or sub-kings, who bore the title of _tudun_. We hear also of the _jugur_, apparently not a proper name, but the title of a chief who contests the supremacy with the _chagan_. _Tarchan_ seems to be a collective word for the Avar nobility.