By these means, the powerful frontier wardens gradually attain an ever greater, and finally a complete, _de facto_ independence, even though the _formal_ bond of feudal suzerainty may for a long time apparently keep together the newly developed principalities. The reader, of course, recalls instances of these typical transitions; all mediæval history is one chain of them; not only the Merovingian and Carolingian Empires, not only Germany, but also France, Italy, Spain, Poland, Bohemia, Hungary, as well as Japan and China,[111] have passed through this process of decomposition, not only once, but repeatedly. And this is no less true of the feudal states of Mesopotamia: great empires follow each other, acquire power, burst asunder time after time, and again are re-united. In the case of Persia, we are expressly told: “Separate states and provinces, by a successful revolt, obtained freedom for a longer or shorter time, and the ‘great king’ at Susa did not always have the power to force them to return to their obedience; in other states, the satraps or warlike chieftains ruled arbitrarily, carrying on the government faithlessly and violently, either as independent rulers or tributary under-kings of the king of kings. The Persian world-empire went to its disintegration an agglomeration of states and lands, without any general law, without ordered administration, without uniform judicial system, without order and enforcement of law, and without possibility of help.”[112] A similar fate overtook its neighbor in the valley of the Nile: “Princes spring from the families of the usurpers, free landlords, who pay land-taxes to nobody but to the king, and rule over certain strips of land, or districts. These district princes govern a territory specifically set apart as pertaining to their official position, and separate from their family possessions. “Later successful warlike operations, perhaps filling in the gap between the Ancient and the Middle (Egyptian) Empire, _together with the gathering in of captives of the wars, who could be utilized as labor motors_, brought a more stringent exploitation of the subjects, a definite determination of the tributes. During the Middle Empire, the power of the princes of the clans rose to an enormous height, they maintained great courts, imitating the splendor of the royal establishment.”[113] “With the decline of the royal authority during a period of decay, the higher officials use their power for personal aims, in order to make their offices hereditary within their families.”[R][114]