"The gods be with you," he panted. "I seek either Proxenus or Clearchus, with a message from Ariaius."

"I'm your man," Proxenus answered. "Speak your mind." I thought it odd that Ariaius would address a message to Proxenus, rather than to his personal friend Menon, who was a Greek officer of equal rank to Proxenus, but I kept silent and merely edged closer to listen. The runner glanced uncertainly at me, and then continued.

"Ariaius asked me to preface my message with a reminder that although he travels with Tissaphernes in his train, he was true to Cyrus and remains loyal to his Hellenic friends. Ariaius bids me warn you to be on your guard tonight against an attack. Tissaphernes has deployed a large force just on the other side of the bridge, and means to destroy it to prevent you from crossing, trapping you between the river and the canal."

I stared at him in amazement. Proxenus acted swiftly. Seizing the man by the scruff of the neck, he half dragged, half pushed him to Clearchus' headquarters, which stood a few hundred yards away, to make him repeat his story. On the way there I caught sight of Asteria as she staggered up from the river to the camp followers' quarters, a yoke across her frail shoulders, bearing two buckets of water, a task to which she was wholly unsuited. Asteria did not see me at first, for her eyes were fixed on the messenger, focusing on nothing else. I glanced at the messenger's face just as he, in turn, looked at her, and with a hint of recognition his mouth tightened slightly in a grim smile and he nodded almost imperceptibly. Asteria flushed white, not pink as might a woman suddenly confronted by a hidden or past lover, but rather pale in fear, and quickly averted her gaze. The whole episode had taken not more than a few seconds, but it was something that stayed with me for weeks afterwards, though I wondered whether I had merely imagined it.

Clearchus' reaction upon receiving the messenger's news was to let fly a string of oaths that sent every man in the vicinity scurrying for cover, hoping that his wrath was hot somehow directed against him. The messenger quaked, for if anything, Clearchus had developed an even more frightening reputation among the Persians than among us, as a result of his execrable treatment of the king's ambassadors. "Let him live," he said grudgingly, for it was apparent from the boy's fear that he was no idle prankster bent on tormenting the Greeks, but rather a genuine messenger from Ariaius, and was telling the truth. Clearchus then sent out Tolmides to summon the officers to his table for a council. The sun was already dropping low in the west, so the matter was urgent.

I attended the meeting with Xenophon, and could see the worry etched on everyone's faces. The men were tired after several days' march, and our position was weak, hemmed in by wide bodies of water passable only by pontoon bridges. Our "island" would be difficult to defend-the terrain was almost perfectly flat, with no natural rises or outcroppings from which we could mount fortifications, and it was ideal for cavalry runs, which the king could send in droves, while we were limited to our forty or so existing horse. Clearchus cursed again and again as he reviewed the situation out loud.

The fact, however, that Ariaius had sent his message not to a friend who knew him intimately, but rather to Proxenus, had raised doubts in Xenophon's mind, and he spoke up for the first time in the presence of the senior officers without first discussing the matter with Proxenus.

"General, with your permission: Ariaius' claim is not logical. Why would the Persians both attack us and eliminate the bridge? If they attack, they will either win or lose. If they win, why destroy such an asset? They will need it afterward to return home, and we would be doomed, bridge or no bridge. If they lose, they will need the bridge all the more, to escape death at our hands, rather than being trapped here on the island."

Clearchus listened to him attentively, with a somewhat surprised look on his face, which I did not know whether to attribute to his having noticed Xenophon in his camp for the first time, or to his actual words. He pondered this for a minute, and then asked the messenger how much country there was between the Tigris and the canal we had passed the morning before.

"A great deal, your lordship, as well as many villages, some cities, and much fruitful land such as that on which you are encamped."

The other officers then saw Xenophon's point, which Clearchus had understood immediately. The Persians had sent this man with a message to be wary of an attack, precisely to dissuade us from cutting the bridge over the Tigris ourselves. This would have afforded us an impregnable position, defended by the river on one side and the canal on the other, with plenty of provisions from the country and villages in between, and able to wring further concessions from Tissaphernes. From our standpoint it was laughable, for since Cyrus' death, there was not a Greek among the entire ten thousand who did not yearn to return home as soon as possible, and be out of this foreign territory with its strange customs and headache-inducing wine. Attempting to hold out against the king's forces, against those odds, was inconceivable. But the Persians remained as fearful of us as we of them, and suspicions of treachery were shared by both sides. Hence the complicated game of cat and mouse Tissaphernes was playing with us, to protect his rear.

Clearchus took no chances, and placed a heavy guard on both ends of the bridge that night, with backup cavalry runners posted to inform him within minutes if an attack had begun. However, he ordered the captains not to breathe a word of the affair to their men; let them get a good night's sleep. Any uproar like the one that had ensued after the battle, which he had quelled with the wild ass story, would this time have much more dire consequences, with the Persians practically within shouting range of us on the other side of the river.

The next morning the army was up before daylight, crossing the thirty-seven vessels that made up the pontoons of the floating bridge before the Persians had even finished their breakfast. Again, Clearchus took every precaution, moving all the heavy troops over first to establish a beachhead and guard against a Persian attack while we were vulnerable on the narrow bridge. Our baggage and camp followers came last, rather than protected in the middle as is usually the case, for our rear was secure, protected by our position on the island. I watched the crossing with Xenophon from a height on the far side. The rising sun reflected red and orange off the glinting river, broken only by the bridge's tenuous line, like a single thread lashing a sleeping Titan to the earth. The bridge bowed outward as the river's current pressed the middle vessels downstream, and it strained in seeming frustration at the restraints holding it fast to the banks at the two ends.

Despite the water's sluggish calm, negotiating a narrow pontoon bridge with wagons and pack animals is tricky business. Like an army or a man, any complex system that appears stable and solid from afar is, from a closer perspective, actually a unit comprising many interconnected components, each engaging in myriad tiny rebellions against the other, constant assertions of independence, and a linked bridge such as this is no exception. The vessels of which it was constructed rocked and tipped, the grass ropes binding them creaked and strained. As each squad of hoplites, each herd of terrified, squealing swine, each tippy cartload of cooking supplies and heavy equipment miraculously made its swaying way across the narrow length, Xenophon let out an audible sigh of relief and offered a small nod of thanks to the gods.

While watching the camp followers I could make out Asteria gamely tramping across with a crowd of other women, bearing a bundle on her shoulders that seemed far larger than she should be required to carry. A feeling of shame that I was unable to do more to help her troubled me greatly during this long phase of marching, tempered only by her smiling dismissals when I asked her about it at night.