He also mentions the important negative fact that he could not find any tomb or mound marking the burial-place of the Medes. The soros, in its present state, is an earthen mound with rather steep sides, between twenty and thirty feet high. The fact of its being a tomb has been proved by recent excavation. Why the Persians landed at Marathon has always been a matter of dispute. The reason given by Herodotus, namely its suitability for cavalry, is not convincing, because the plain of Athens itself, not to speak of the Thriasian plain, is more suitable for cavalry operations. Moreover, the Persians made no use of this arm during the battle. The plan of the Persian campaign, as far as Athens was concerned, was based on calculations dependent on circumstances other than purely military, to which it is necessary to turn, in order to account for the adoption of a design for which no adequate reason of a purely strategic nature can be suggested. Very little is known of the history of the internal politics at Athens during the decade between 500 and 490 B.C. In the previous decade there had been a fierce struggle between the aristocratic and democratic parties under Isagoras and Kleisthenes respectively, which, after several turns of fortune, had apparently ended in the victory of the democrats. But in spite of the absence of direct reference to this special side of history in the records of the first ten years of the fifth century, certain well-attested incidents show that the struggle for supremacy between the parties had not been decided before the new century began. Greek cities were rarely free from intrigue; and it would seem to have been unusually rife in the Athens of 490. It has already been pointed out that in a version of the tale of Marathon current in Herodotus’ own time the Alkmæonidæ were accused of having been in league with the Persian. Herodotus’ defence of them, by its manifest weakness, is strong evidence against them. They were conspicuous for their hatred of tyranny, he says. They had driven out Hippias. He might have added that they had also driven out Peisistratos, but had been instrumental in restoring him. He ignores their relations with Peisistratos, not to say anything of those with Kleisthenes of Sikyon. He forgets for the moment that they had been in the pay of a Lydian king. [Illustration: BATTLE OF MARATHON London: John Murray, Albemarle St. _Stanford’s Geog^l. Estab^t. London._ ] #POLITICAL PARTIES AT ATHENS.# The charge made with regard to their conduct at this time was that they signalled to the Persian fleet at Marathon by means of a shield, that Athens, in the absence of the Athenian army, lay open, and that a party within the city would admit the invaders.