And here it may be well to remark what terrible consequences to mankind the ambition of a single man may cause. The invasion of Greece, and all that came from it, can be traced in a direct line of events from the deeds of Histiaeus, tyrant of Miletus, who first saved Darius from annihilation by the Scythians, then roused the Ionians to rebellion, and, finally, through the medium of Aristagoras, induced the Athenians to come to their aid and take part in the burning of Sardis. This roused Darius, who had dwelt at Susa for many years in peace, to a thirst for revenge on Athens, and gave rise to that series of invasions which ravaged Greece for many years, and whose fitting sequel was the invasion and conquest of Persia by Alexander the Great, a century and a half later. And now, with this preliminary statement, we may proceed with our tale. No sooner had the Ionian revolt been brought to an end, and the Ionians punished for their daring, than the angry Oriental despot prepared to visit upon Athens the vengeance he had vowed. His preparations for this enterprise were great. His experience in Scythia had taught him that the Western barbarians--as he doubtless considered them--were not to be despised. For two years, in every part of his vast empire, the note of war was sounded, and men and munitions of war were actively gathered. On the coast of Asia Minor a great fleet, numbering six hundred armed triremes and many transports for men and horses, was prepared. The Ionian and AEolian Greeks largely manned this fleet, and were forced to aid their late foe in the effort to destroy their kinsmen beyond the archipelago of the AEgean Sea. An Athenian traitor accompanied the Persians, and guided their leader in the advance against his native city. We have elsewhere spoken of Pisistratus, the tyrant of Athens, whose treason Solon had in vain endeavored to prevent. After his death, his sons Hipparchus and Hippias succeeded him in the tyranny. Hipparchus was killed in 514 B.C., and in 511 Hippias, who had shown himself a cruel despot, was banished from Athens. He repaired to the court of King Darius, where he dwelt many years. Now he came back, as guide and counsellor to the Persians, hoping, perhaps, to become again a despot of Athens; but only, as the fates decreed, to find a grave on the fatal field of Marathon. The assault on Greece was a twofold one. The first was defeated by nature, the second by man. A land expedition, led by the Persian general Mardonius, crossed the Hellespont in the year 493 B.C., proposing to march to Athens along the coast, and with orders to bring all that were left alive of its inhabitants as captives to the great king. On marched the great host, nothing doubting that Greece would fall an easy prey to their arms. And as they marched along the land, the fleet followed them along the adjoining sea, until the stormy and perilous promontory of Mount Athos was reached.