Upon the expulsion of Hippias the direction of Athenian politics passed into the hands of Cleisthenes, son of Megacles, the head of the Alemæonidæ. He soon found a rival in Isagoras, a man of noble extraction, whose popularity with the rich and noble preponderated over his own; and being in consequence driven to advocate the popular cause, and thus recovering the ascendant, he introduced several changes tending to make the constitution more democratical. Isagoras sought to regain his advantage by foreign aid; and at his suggestion Cleomenes, one of the kings of Sparta, required the expulsion of the Alemæonidæ, as an atonement for the sacrilegious murder of Cylon’s partisans, in which they had been the chief actors. Offensive as such an interference appears, the religious feelings of Greece gave weight to the requisition, which was besides backed by the whole power of Sparta: and in obedience to it, Cleisthenes and his chief supporters withdrew. Not content with this, the Spartan king went with a small force to Athens, and proceeded to banish seven hundred families as concerned in the sacrilege, to change the forms of the constitution, and place all power in the hands of Isagoras and his friends. But he miscalculated the forbearance of the Athenians. Fearful as they were of a rupture with their powerful rival, they flew to arms, and besieged Cleomenes in the citadel. On the third day he and his troops surrendered on condition that they should be allowed to depart, and Cleisthenes, returning, reassumed the direction of affairs. His first object was to find some assistance in the war which appeared inevitable; and as the Persian empire was now at its height, he sent ambassadors to Sardis, where the satrap or governor of Lydia resided, to request admission to the Persian alliance. The satrap inquired who the Athenians were, and where they lived, and then scornfully answered, that if they would give earth and water to King Darius, in token of subjection, their request should be granted; otherwise they must depart. The ambassadors complied, but on returning to Athens they were strongly censured. This was the first public transaction between Greece and Persia.