^ Thus, Artaphernes, satrap of Sardes, had a cadastral survey made of the territory of the Ionians, and by the results of this survey he regulated the imposition of taxes, “which from that time up to the present day are exacted according to his ordinance.”

Attached to each satrap was a secretary of state, who ostensibly acted as his chancellor, but whose real function was to exercise a secret supervision over his conduct and report upon it to the imperial ministers.* The Persian troops, native militia and auxiliary forces quartered in the province, were placed under the orders, moreover, of a general, who was usually hostile to the satrap and the secretary.** These three officials counterbalanced each other, and held each other mutually in check, so that a revolt was rendered very difficult, if not impossible.  All three were kept in constant communication with the court by relays of regular couriers, who carried their despatches on horseback or on camels, from one end of Asia to the other, in the space of a few weeks.***

     * The role played by the secretary is clearly indicated by
     the history of Orotes, satrap of Sardes.

** While Darius appoints his brother Artaphernes satrap of Lydia, he entrusts the command of the army and the fleet to Otanes, son of Sisamnes.  Similarly several generals are met with at the side of Artaphernes in the Ionic revolt.

*** Xenophon compares their speed in travelling to the flight of birds.  A good example of the use of the camel for the postal service is cited by Strabo, on the occasion of the death of Philotas and the execution of Parmenion under Alexander.

The most celebrated of the post-roads was that which ran from Sardes to Susa through Lydia and Phrygia, crossing the Halys, traversing Cappadocia and Cilicia, and passing through Armenia and across the Euphrates, until at length, after passing through Matiene and the country of the Cossaeans, it reached Elam.  This main route was divided into one hundred and eleven stages, which were performed by couriers on horseback and partly in ferry-boats, in eighty-four days.  Other routes, of which we have no particular information, led to Egypt, Media, Bactria, and India,* and by their means the imperial officials in the capital were kept fully informed of all that took place in the most distant parts of the empire.  As an extra precaution, the king sent out annually certain officers, called his “eyes” or his “ears,"** who appeared on the scene when they were least expected, and investigated the financial or political situation, reformed abuses in the administration, and reprimanded or even suspended the government officials; they were accompanied by a body of troops to support their decisions, whose presence invested their counsels with the strongest sanction.*** An unfavourable report, a slight irregularity, a mere suspicion, even, was sufficient to disqualify a satrap.  Sometimes he was deposed, often secretly condemned to death without a trial, and the execution of the judgment was committed even to his own servants.