He is desirous of showing that unlimited power is ruinous to any state, and hence he is led to attribute a tyrannical spirit to the first Dorian kings.

The decay of Argos and the destruction of Messene are adduced by him as a manifest proof of their failure; and Sparta, he thinks, was only preserved by the limitations which the wisdom of successive legislators introduced into the government.

But there is no more reason to suppose that the Dorian rule of life which was followed at Sparta ever prevailed in Argos and Messene, than to assume that Dorian institutions were framed to protect the Greeks against the power of Assyria; or that the empire of Assyria was in any way affected by the Trojan war; or that the return of the Heraclidae was only the return of Achaean exiles, who received a new name from their leader Dorieus.

Such fancies were chiefly based, as far as they had any foundation, on the use of analogy, which played a great part in the dawn of historical and geographical research.

Because there was a Persian empire which was the natural enemy of the Greek, there must also have been an Assyrian empire, which had a similar hostility; and not only the fable of the island of Atlantis, but the Trojan war, in Plato's mind derived some features from the Persian struggle.