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.