19. First attack upon Greece, particularly Athens. Darius, already enraged against the Athenians by the firing of Sardes, is still further instigated by the suggestions of the banished tyrant of Athens, Hippias, the son of Pisistratus. This prince, who had fled to the Persian court, was evidently the animating spirit of the whole undertaking. Although the first attempt, made under the command of Mardonius, was thwarted by a tempest, yet the mighty expedition which afterwards followed, was undertaken with so much more prudence, and conducted with so much knowledge of the country, that no one can fail to recognize the guiding hand of Hippias. Even the battle of Marathon, which seems to have been but a diversion on the side of the Persians, would not have decided the war, had not the activity of Miltiades defeated the principal design of the enemy upon Athens. 20. It may be said that Darius, by these foreign wars, debilitated the kingdom which he endeavoured to extend; this circumstance, however, it cannot be denied, increases the merit which he has of perfecting the internal organization of the empire. His reign constitutes precisely that period which must enter into the history of every nomad race that has attained to power, and is advancing towards political civilization; a period at which it becomes visible that the nation is endeavouring to obtain a constitution, however gradual the progress towards it. 21. Division of the empire into twenty _satrapies_, and the imposition of a regular tribute on each. This division at first depended solely on that of the various tributary races, but from it gradually arose a geographic division, in which the ancient distinction of countries was for the most part preserved. Proofs that the division into satrapies was originally a mere arrangement for the civil government and collection of taxes, distinct from military power. Duties of the satraps. The attention they were to pay to the cultivation and improvement of the land; to the collection of the imposts; to the execution of the royal commands relating to provincial affairs. An abuse of this institution, at a later period, placed in the hands of these satraps the command also of the troops.--Various means of keeping the satraps in a state of dependence: royal secretaries appointed for each, who were to be the first to receive the king's commands.--Periodical visits paid to the provinces by commissioners under the direct appointment of the king, or by the king himself accompanied with an army.--Establishment of couriers in every part of the empire, for the purpose of securing a safe and rapid communication with the provinces, as was the case also in the Mongol countries; (not a regular post, however, the institution here alluded to being intended only for the court.)