forts, or the road was defended from post to post. And if an enemy invaded from outside he found in them points of resistance, and the Persians points of support. The guidance and control of the viceroys was not confined to the rapid and lively communications between them and the king. The Greeks tell us that the king travelled every year to this or that province in order to review the troops, and examine the cultivation of the soil. Where the king did not make a visitation in person, he did so by confidential ministers. We are further informed that these visitations were entrusted to the princes of the royal house.[358] Where the king found that the land was populous and well cultivated, the forests in good order, and the fields full of the fruits which the land produced, he distinguished the governor by gifts and honours. But where he found the land thinly populated and badly cultivated, whether it was owing to the severity, the neglect, or the extortion of the satrap, the satrap was punished and removed from his place.[359] The charge of the whole country lay on the chief overseer, the high official who bore the title of the "king's eye." In the Persians of Aeschylus, the chorus inquire of Xerxes, "Where his faithful eye has remained?" Herodotus notices as an arrangement of the Median kingdom, that the king named a man especially devoted to him, his "Eye." We see that unexpected inspections were made by the "Eye" of the Persian king, and that his subordinates, who were not known to be such, carried on a minute superintendence over the conduct of the satraps, the other officers, and the subject people.[360] Still more mysterious was the work of the officers who were known as the king's "Ears." They cannot have been far removed from spies. We saw to what an extent the princes of India carried on the system of secret espionage. Herodotus told us in regard to Deioces that his spies and informers were in every land, and a Persian proverb said, "The king has many eyes and ears." The Greeks declare that the Persian spies did not always content themselves with relating what they had heard, but told much besides in order to show their zeal. Accusation was received with favour by the king and rewarded by distinctions and presents.[361] We saw what control was exercised on the great roads, the arteries of communication. Owing to the number of guard-houses in each road, which repeated the inquiries of the first, any one at the court was in a position to compare the accounts of the commanders, and to control them. No one passed even the borders of Babylonia without proving who he was, and of what city, and why he was travelling.[362] In this way every suspicious circumstance was brought to light, and it was certain that no conspiracy or rebellion could be contrived without some indications being received at the court of the king.