Still, however, the Empire was not wholly tranquillized.  A revolt in Susiana, suppressed by the conspirator Gobryas, and another among the Sacse of the Tigris, quelled by Darius in person, are recorded on the rock of Behistun, in a supplementary portion of the Inscription.  We cannot date, unless it be by approximation, these various troubles; but there is reason to believe that they were almost all contained within a space not exceeding five or six years.  The date of the Behistun Inscription is fixed by internal evidence to about B.C. 516-515—­in other words, to the fifth or sixth year of the reign of Darius.  Its erection seems to mark the termination of the first period of the reign, or that of disturbance, and the commencement of the second period, or that of tranquillity, internal progress, and patronage of the fine arts by the monarch.

It was natural that Darius, having with so much effort and difficulty reduced the revolted provinces to obedience, should proceed to consider within himself how the recurrence of such a time of trouble might be prevented.  His experience had shown him how weak were the ties which had hitherto been thought sufficient to hold the Empire together, and how slight an obstacle they opposed to the tendency, which all great empires have, to disruption.  But, however natural it might be to desire a remedy for the evils which afflicted the State, it was not easy to devise one.  Great empires had existed in Western Asia for above seven hundred years, and had all suffered more or less from the same inherent weakness; but no one had as yet invented a cure, or even (so far as appears) conceived the idea of improving on the rude system of imperial sway which the first conqueror had instituted.  It remained for Darius, not only to desire, but to design—­not only to design, but to bring into action—­an entirely new form and type of government.  He has been well called “the true founder of the Persian state.”  He found the Empire a crude and heterogeneous mass of ill-assorted elements, hanging loosely together by the single tie of subjection to a common head; he left it a compact and regularly organized body, united on a single well-ordered system, permanently established everywhere.

On the nature and details of this system it will be necessary to speak at some length.  It was the first, and probably the best, instance of that form of government which, taking its name from the Persian word for provincial ruler, is known generally as the system of “satrapial” administration.  Its main principles were, in the first place, the reduction of the whole Empire to a quasi-uniformity by the substitution of one mode of governing for several; secondly, the substitution of fixed and definite burthens on the subject in lieu of variable and uncertain calls; and thirdly, the establishment of a variety of checks and counterpoises among the officials to whom it was necessary that the crown should delegate its powers, which tended greatly to the security of the monarch and the stability of the kingdom.  A consideration of the modes in which these three principles were applied will bring before us in a convenient form the chief points of the system.