Polycleitus is said to have written a treatise in which he gave exact rules for the proportions of the different parts of the body. This was called "the canon" of Polycleitus, and there is good reason to believe that the Doryphorus was called by the same name, "the canon," because it was fashioned according to the rules laid down by Polycleitus in his treatise. His pupils and followers are mentioned with honor by the Greek authors of his time, but I need not mention them here. The art of Phidias and Polycleitus was the art of Greece at its best period. After the close of the Persian wars the people of Greece were a religious and patriotic people. The Persian wars developed the best quality of character, for these wars were waged against a foreign foe, and the Greeks were defending their freedom and their civilization, and at the end of the struggle Pericles, who guided them to their greatest prosperity, was a statesman and a man of high aims; he was a gentleman as well as a strong ruler. The Peloponnesian war, on the contrary, was a civil war, and it divided the Greeks among themselves and roused the evil passions of friend against friend all over their country. It was the cause of selfishness, treachery, and immorality, and one of its worst effects was seen in the loss of religious tone among the people: their old contented simplicity of life and thought was gone; every man thought only of himself, and the nation began to sink into the condition which at last made it an easy prey to the Macedonians. We have studied all these wars in our histories, but perhaps we have not thought how much they affected sculpture and the other arts, and brought them down from the lofty heights of the Periclean age. But there were still men who strove to be great and grand in morals and in intellect, and perhaps strove all the more earnestly for this on account of the decline they saw about them. Few countries in any age have had more splendid men than Socrates, Plato, Euripides, Aristophanes, Pelopidas, Epaminondas, Demosthenes, Dion, and Timoleon, and these all lived between the Peloponnesian and the Macedonian wars. And while the arts were less grand than before, they did not fall into decline for some years, though they took on new features. The gods who had been mostly represented were less often the subjects of the sculptor, and when they were so they were softened and made less awful in their effect. Other gods were more freely taken for models, such as came nearer to human life and thought, because less sublime in their attributes and characters. Among these were Venus as a lovely woman rather than as the great mother of all living creatures, and Eros, or Love; while Plutus, or Wealth, and satyrs, nymphs, and tritons were multiplied in great numbers.