In spite of the strong opinion which he had expressed in reply to Klearchus, Cyrus now really began to conceive that no battle would be hazarded by his enemies; especially as in the course of this last day’s march, he came to a broad and deep trench (thirty feet broad and eighteen feet deep), approaching so near to the Euphrates as to leave an interval of only twenty feet for passage. This trench had been dug by order of Artaxerxes across the plain, for a length said to be of twelve parasangs (about forty-two English miles, if the parasang be reckoned at thirty stadia), so as to touch at its other extremity what was called the walls of Media.[79] It had been dug as a special measure of defence against the approaching invaders. Yet we hear with surprise, and the invaders themselves found with equal surprise, that not a man was on the spot to defend it; so that the whole Cyreian army and baggage passed without resistance through the narrow breadth of twenty feet. This is the first notice of any defensive measures taken to repel the invasion,—except the precaution of Abrokomas in burning the boats at Thapsakus. Cyrus had been allowed to traverse all this immense space, and to pass through so many defensible positions, without having yet struck a blow. And now Artaxerxes, after having cut a prodigious extent of trench at the cost of so much labor,—provided a valuable means of resistance, especially against Grecian heavy-armed soldiers,—and occupied it seemingly until the very last moment,—throws it up from some unaccountable panic, and suffers a whole army to pass unopposed through this very narrow gut. Having surmounted unexpectedly so formidable an obstacle, Cyrus as well as the Greeks imagined that Artaxerxes would never think of fighting in the open plain. All began to relax in that careful array which had been observed since the midnight review, insomuch that he himself proceeded in his chariot instead of on horseback, while many of the Greek soldiers lodged their arms on the waggons or beasts of burden.[80] [79] From Pylæ to the undefended trench, there intervened three entire days of march, and one part of a day; for it occurred in the fourth day’s march. Xenophon calls the three entire days, twelve parasangs in all. This argues short marches, not full marches. And it does not seem that the space of ground traversed during any one of them can have been considerable. For they were all undertaken with visible evidences of an enemy immediately in front of them; which circumstance was the occasion of the treason of Orontes, who asked Cyrus for a body of cavalry, under pretence of attacking the light troops of the enemy in front, and then wrote a letter to inform Artaxerxes that he was about to desert with his division. The letter was delivered to Cyrus, who thus discovered the treason.