Once a year, according to Xenophon, or more probably at irregular intervals, an officer came suddenly down from the Court with a commission to inspect a province.

Such persons were frequently of royal rank, brothers or sons of the king.

They were accompanied by an armed force, and were empowered to correct whatever was amiss in the province, and in case of necessity to report to the crown the insubordination or incompetency of its officers.

If this system had been properly maintained, it is evident that it would have acted as a most powerful check upon misgovernment, and would have rendered revolt almost impossible.
Another mode by which it was sought to secure the fidelity of the satraps and commandants was by choosing them from among the king's blood relations, or else attaching them to the crown by marriage with one of the princesses.

It was thought that the affection of sons and brothers would be a restraint upon their ambition, and that even connections by marriage would feel that they had an interest in upholding the power and dignity of the great house with which they had been thought worthy of alliance.