Persia, until the time of Anushirwan, had been divided into a multitude of provinces, the satraps or governors of which held their office directly under the crown. It was difficult for the monarch to exercise a sufficient superintendence over so large a number of rulers, many of them remote from the court, and all united by a common interest. Chosroes conceived the plan of forming four great governments, and entrusting them to four persons in whom he had confidence, whose duty it should be to watch the conduct of the provincial satraps to control them, direct them, or report their misconduct to the crown. The four great governments were those of the east, the north, the south, and the west. The east comprised Khorassan, Seistan, and Kirman; the north, Armenia, Azer-bijan, Ghilan, Koum, and Isfahan; the south, Fars and Ahwaz; the west, Irak, or Babylonia, Assyria, and Mesopotamia.
It was not the intention of the monarch, however, to put a blind trust in his instruments. He made personal progresses through his empire from, time to time, visiting each province in turn and inquiring into the condition of the inhabitants. He employed continually an army of inspectors and spies, who reported to him from all quarters the sufferings or complaints of the oppressed, and the neglects or misdoings of those in authority. On the occurrence of any specially suspicious circumstance, he appointed extraordinary commissions of inquiry, which, armed with all the power of the crown, proceeded to the suspected quarter, took evidence, and made a careful report of whatever wrongs or malpractices they discovered.
When guilt was brought home to incriminated persons or parties, the punishment with which they were visited was swift and signal. We have seen how harsh were the sentences passed by Chosroes upon those whose offences attacked his own person or dignity. An equal severity appears in his judgments, where there was no question of his own wrongs, but only of the interests of his subjects. On one occasion he is said to have executed no fewer than eighty collectors of taxes on the report of a commission charging them with extortion. Among the principal reforms which Chosroes is said to have introduced was his fresh arrangement of the taxation. Hitherto all lands had paid to the State a certain proportion of their produce, a proportion which varied, according to the estimated richness of the soil, from a tenth to one-half. The effect was to discourage all improved cultivation, since it was quite possible that the whole profit of any increased outlay might be absorbed by the State, and also to cramp and check the liberty of the cultivators in various ways, since the produce could not be touched until the revenue official made his appearance and carried off the share of the crop which he had a right to take. Chosroes resolved to substitute a land-tax for the proportionate payments in kind, and thus at once to set the cultivator at liberty with respect to harvesting his crops and to allow him the entire advantage of any augumented production which might be secured by better methods of farming his land. His tax consisted in part of a money payment, in part of a payment in kind; but both payments were fixed and invariable, each measure of ground being rated in the king's books at one dirhem and one measure of the produce. Uncultivated land, and land lying fallow at the time, were exempt; and thus the scheme involved, not one survey alone, but a recurring (annual) survey, and an annual registration of all cultivators, with the quantity of land under cultivation held by each, and the nature of the crop or crops to be grown by them. The system was one of much complication, and may have pressed somewhat hardly upon the poorer and less productive soils; but it was an immense improvement upon the previously existing practice, which had all the disadvantages of the modern tithe system, aggravated by the high rates exacted and by the certainty that, in any disputed case, the subject would have had a poor chance of establishing his right against the crown. It is not surprising that the caliphs, when they conquered Persia, maintained unaltered the land system of Chosroes which they found established, regarding it as, if not perfect, at any rate not readily admitting of much improvement.