* The date of the death of Polycrates must be placed between
     that of the conquest of Egypt and that of the revolt of
     Gaumata, either in 524 or 523 B.C.

     ** The reinstatement of Syloson may be placed in 516 B.C.,
     about the time when Darius was completing the reorganisation
     of the empire and preparing to attack Greece.

This constant intervention of the foreigner was in evident contradiction to the spirit which had inspired the reorganisation of the empire.  Just when efforts were being made to strengthen the imperial power and ensure more effective obedience from the provincials by the institution of satrapies, it was impossible to put up with acts of unwarrantable interference, which would endanger the prestige of the sovereign and the authority of his officers.  Conquest presented the one and only natural means of escape from the difficulties of the present situation and of preventing their recurrence; when satraps should rule over the European as well as over the Asiatic coasts of the AEgean, all these turbulent Greeks would be forced to live at peace with one another and in awe of the sovereign, as far as their fickle nature would allow.  It was not then, as is still asserted, the mere caprice of a despot which brought upon the Greek world the scourge of the Persian wars, but the imperious necessity of security, which obliges well-organised empires to subjugate in turn all the tribes and cities which cause constant trouble on its frontiers.  Darius, who was already ruler of a good third of the Hellenic world, from Trebizond to Barca, saw no other means of keeping what he already possessed, and of putting a stop to the incessant fomentation of rebellion in his own territories, than to conquer the mother-country as he had conquered the colonies, and to reduce to subjection the whole of European Hellas.

CHAPTER II—­THE LAST DAYS OF THE OLD EASTERN WORLD

THE MEDIAN WAR—­THE LAST NATIVE DYNASTIES OF EGYPT—­THE EASTERN WORLD ON THE EVE OP THE MACEDONIAN CONQUEST.

The Persians in 512 B.C.—­European Greece and the dangers which its independence presented to the safety of the empire—­The preliminaries of the Median wars:  the Scythian expedition, the conquest of Thrace and Macedonia—­The Ionic revolt, the intervention of Athens and the taking of Sardes; the battle of Lade—­Mardonius in Thrace and in Macedonia.

The Median wars—­The expedition of Datis and Artaphernes:  the taking of Eretria, the battle of Marathon (490)—­The revolt of Egypt under Khabbisha; the death of Darius and the accession of Xerxes I.—­The revolt of Babylon under Shamasherib—­The invasion of Greece:  Artemision, Thermopylae, the taking of Athens, Salamis—­Platsae and the final retreat of the Persians:  Mycale—­The war carried on by the Athenians and the league of Delos:  Inaros, the campaigns in Cyprus and Egypt, the peace of Oallias—­The death of Xerxes.