But although they had now seen the last of Tissaphernes, the Hellenes were still a very long way from the end of their journey. Difficulties of another and more serious kind still lay before them, and the question of their further route caused the generals great anxiety. For in front of the fruitful valley in which they were encamped, there stretched before them a stern and rugged mountain-country inhabited by a nation of savages.
The limit of this mountain district was the river Tigris, and the only way of avoiding it was by crossing the Tigris. No path could be found by which they could pass between the mountains and the river, for immense rocks stretched out far over the water, so that there was not space for even a single person to go by.
But the river was far too deep and broad to be forded, and they had no other means of crossing. When they tried to measure its depth with their long spears, they could not reach the bottom, even close to the shore.
Whilst the generals were consulting together as to what could be done, a Rhodian soldier came to them to ask for an audience, and said, "If you will promise me a talent of silver, and provide me with all that I shall need for carrying out my plan, I will build you a bridge over the Tigris capable of bearing two thousand hoplites."
Then he went on to explain his plan. "We have here," he said, "a great many cows, sheep, goats and asses. All these animals must give me their skins, for I shall want two thousand leather bags. I shall also want all the straps used for the baggage animals. The skins must be inflated, and tied up securely. I shall then attach one of the straps to either end of each skin so that it can be fastened to the next one, and steady it in the water with large stones let down from the under side to serve as anchors. When the skins are all in their places and fastened together, I shall cover them thoroughly with earth and brushwood to prevent them from being slippery, and the bridge will be complete. Each skin will bear the weight of two men, so that you will have a bridge able to carry four thousand."
The generals agreed that it was an excellent idea, but unhappily they could not turn it to any account, for on the further side of the river, troops of Persian cavalry were already collected to oppose their crossing, and by them the men employed in working at the bridge would be shot down one by one, long before it was sufficiently finished to carry the soldiers across.
The crossing of the river was thus out of the question, and there remained nothing but the road over the mountains, although they knew not whither it led. They were like mariners driven out of their course by violent storms, who neither know where they are, nor what is before, or behind, or on either side of them. Gladly would the Hellenes have given a good deal of their scanty store of money for a small sheet of paper which to-day can be bought anywhere for a few pence,—a map of the country that lay before them. But in those days no such thing had ever been heard of.
All they could do was to question the prisoners, and from them they learnt that southwards, in the direction from whence they had come, were the provinces of Babylonia and Media, to the east were the cities of Susa and Babylon, to the west the provinces of Lydia and Ionia, and that the road northwards over the mountains would lead them through the land of the Carduchians, a fierce, war-loving race, who had never been conquered. Once the Great King had sent into their country an army of 120,000 men, to subdue them, but of all that great host not one had ever seen his home again.
If the Hellenes should succeed in getting through the country of the Carduchians, they would then reach the province of Armenia, and after that they would be able to journey on without further hindrance.