(M596) The impression produced on the Grecian mind by the successful retreat of the Ten Thousand was profound and lasting. Its most obvious effect was to produce contempt for Persian armies and Persian generals, and to show that Persia was only strong by employing Hellenic strength against the Hellenic cause. The real weakness of Persia was thus revealed to the Greeks, and sentiments were fostered which two generations afterward led to the expeditions of Alexander and the subjection of Asia to Grecian rule. CHAPTER XXI. THE LACEDÆMONIAN EMPIRE. (M597) I have already shown that Sparta, after a battle with the Argives, B.C. 547, obtained the ascendency in the southern part of the Peloponnesus, and became the leading military State of Greece. This prestige and power were not lost. The severe simplicity of Spartan life, the rigor of political and social institutions, the aristocratic form of government, and above all the military spirit and ambition, gave permanence to all conquests, so that in the Persian wars Sparta took the load of the land forces. The great rival power of Sparta was Athens, but this was founded on maritime skill and enterprise. It was to the navy of Athens, next after the hoplites of Sparta, that the successful resistance to the empire of Persia may be attributed. (M598) After the Persian wars the rivalship between Athens and Sparta is the most prominent feature in Grecian history. The confederacy of Delos gave to Athens supremacy over the sea, and the great commercial prosperity of Athens under Pericles, and the empire gained over the Ionian colonies and the islands of the Ægaean, made Athens, perhaps, the leading State. It was the richest, the most cultivated, and the most influential of the Grecian States, and threatened to absorb gradually all the other States of Greece in her empire.