According to Xenophon's description, Cyrus was of a kindly disposition, eager to instruct himself, and so ambitious that he shrank from no effort and no danger.[573] With the Greeks he passes not only for the founder of the dominion of the Persians, but for the author of excellent arrangements in the kingdom. From this point of view Xenophon wrote his treatise on Cyrus. By his example he wished to prove to the Greeks how the empire over nations could be gained, how a great kingdom could be founded and maintained, how a ruler could command obedience even among those who had never seen him and were separated by great distances. It is a historical romance which he has written on Cyrus; but he knew the Persian empire, and could not advance anything absolutely in contradiction to the current opinion of the Greeks about Cyrus. According to him the relation of Cyrus to the Persians rested on a kind of compact. When his son had subjugated the nations far and wide, Cambyses collected the elders of the Persians and the officers who held the highest places, and told them the Persians had elected Cyrus to be their general, and given him the army; Cyrus had extended their power over Asia, and gained glory among all men; he had made the bravest men in the army rich, and found pay and food for all the soldiers. If this relation were maintained it would be for the advantage of both parties; if, on the other hand, Cyrus sought to rule over the Persians with the same caprice as over other nations, or the Persians should attempt to take the command from him, each would do the greatest harm to the other. Let Cyrus, therefore, undertake to protect Persia and uphold the Persian laws, and the Persians to render Cyrus any service that he needed against rebellion and enemies. "After me," Cambyses concludes, "Cyrus will be king, and whenever he comes to Persia he will offer for you the sacrifice which I am offering now. If he is in a foreign land, it will be best for the noblest of our family to offer sacrifices to the gods." "What Cambyses proposed was approved by Cyrus and the Persians with invocations to the gods, and the arrangement is still observed on both sides."[574] Plato even puts Cyrus on the same level as Lycurgus, the founder of the constitution of Sparta. He gives Dion the choice of rivalling the ancient Lycurgus or Cyrus, or any one else who may be distinguished by moral excellence and political wisdom.[575] According to the Laws, Cyrus, brought up from his youth in the camp and surrounded by danger, became a skilful general, and as a ruler kept before his eyes the prosperity of the state. In the same book we are told that the monarchical form of government attained its most complete state among the Persians, and the democratic among the Athenians. But as the Persian state pursued absolute dominion, and the Attic uncontrolled freedom, neither discovered the correct limit; though in ancient times they had observed due moderation.