Early on the next morning the garrison of Nisibis arrived, increasing the strength of the Persians to 50,000 men of all arms, which was twice the strength of Belisarius's forces. He commented, when he heard the news: 'Few as are the generals capable of controlling in battle an army of forty thousand men, there are still fewer who can control fifty thousand.' His conjecture that Firouz was somewhat embarrassed by the unwieldy size of his forces appeared to be justified. For they were now reorganized into two equal lines of battle, one supporting the other. Belisarius commented: 'A drill-sergeant's solution. He could have used the front formations to mask Daras, and with the remainder struck at my communications!' Meanwhile he and the Master of Offices sent a joint letter to Firouz, suggesting that he withdraw the Persian army to Nisibis instead of forcing a desperate and unnecessary battle. The wording of this letter was for the most part Belisarius's, and one characteristic sentence has been recorded: 'Nobody with the smallest claim to common sense enjoys fighting, even when fighting is necessary; and the general who begins hostilities has a grave responsibility not only to the men under his command but to his whole nation for the distresses and horrors that are inseparable from war.' The Master of Offices contributed a passage to the effect that negotiations for peace were about to be resumed by Justinian, whose ambassador was now on the way from Antioch, but that a clash at Daras would put an immediate end to all hopes of a peaceful settlement.
Firouz replied that Persia had been so often deceived by the peaceful protests of Roman ambassadors that her patience was exhausted: war was now the only remedy for wrongs. No peace treaty could any longer be taken seriously, especially if concluded by Roman oaths.
Belisarius and the Master of Offices replied that they had said as much as could honourably be said, and that the present correspondence would be fixed upon the Imperial standard next day — true copies of their own letters and the Persian reply — as a witness to the God of the Christians that the Romans had made every effort to avoid a needless battle.
Firouz replied: 'The Persians have a God too, more ancient than yours, and more powerful, and he will bring us safely into Daras tomorrow.'
Belisarius now addressed his forces, which were drawn up in mass behind the trench in the centre. He pitched his voice high and spoke slowly and enunciated clearly, so that every man heard as plainly as if it had been a conversation in a private room; and he spoke familiarly, first in Camp Latin and then in Greek, so that all might understand. He explained that the reason why Roman armies had not in the past invariably beaten the Persians, who were inferior to them alike in courage, arms and physique, was merely that their discipline had been faulty; and this was an easily remedied matter. If every man obeyed his officers, during both advance and retirement, defeat would be impossible. A battle should be fought by the common soldier as if it were a drill; and in drill it was surely easier to obey than to break ranks or act on a private impulse? The tactical control of the battle must remain in the responsible hand of the commanding general, namely himself, and he had given clear alternative instructions to Ids subordinate officers as to how to behave in this possible development of the battle and that. The common soldier should be so occupied with his own weapons, and with keeping formation, as to have no time to speculate irrelevantly on the general progress of the fighting. Full reliance must be placed on the tried intelligence and loyalty of the officers. He also made a laughing reference to the enemy infantry, only half of which consisted of trained soldiers. 'You Roman recruits have in a short time learned to do one thing well, which is to shoot strong and straight; their recruits have also learned a single military art, and that is to protect themselves behind those enormous shields of theirs. They are merely crowds of rustics brought up for effect, like stage armies, and will prove a great embarrassment to their generalissimo before the day is over. They have spears in their hands, it is true, but this no more makes spearmen of them than if one were to arm them with flutes and call them snake-charmers!'
The warning was then given from the look-out tower that the Persians were beginning to marshal their forces; so, with loud cheers for Belisarius, the parade moved off. The heavy cavalry rode to their stations on the flanks, the light cavalry posted themselves in the two angles of the re-entrant, the archers once more lined the nearer trenches, the phalanxes of spearmen posted themselves at the bridges with the javelin men behind and beside them. Then Pharas, the little bow-legged leader of the Herulian Huns, trotted up to Belisarius and said to him in the almost unintelligible trade-Greek that these Crimean savages use: 'I not harm the Persians, not much, here under tall walls: send I behind that hill on the left, away. I hide behind that hill- When Persians come, I hurry to their behind; I charge, shoot, shoot.'
Belisarius eyed Pharas steadily, who dropped his gaze. Pharas evidently doubted the issue of the day and wished to be in a neutral position; his final charge would be against whichever side seemed to be winning the battle. Belisarius noticed that Pharas's finger was bleeding from a slight scratch: he therefore quickly seized it, for they were knee to knee, and thrusting it into his mouth sucked it. Then he said: 'I have eaten your blood, Pharas: you shall be my anda, my blood-brother. Go now, dear Pharas, my anda, and do as you say. Hide behind that hill and charge the Persians neither too soon nor too late.' Pharas complained whimpering: 'You eat my blood, now give me yours, anda!' For by this one-sided action he had come (according to Hunnish superstition) under Belisarius's magical power. But Belisarius replied: 'After the charge has been made you may cat your fill. I have no blood to spare now, anda.' Thus Pharas was securely bound to loyalty.
The Persians held their positions all the morning, until they heard the bugles blowing from the fortifications as a signal for the ration men to fetch the midday meal up to the trenches. As soon as Firouz calculated that the distribution of food was about to start, he launched the attack. Persian soldiers are accustomed to cat in the late afternoon, and consequently do not feel hungry until the sun is low in the sky, whereas the call of the Roman appetite comes when the bugle sounds at midday. However, Belisarius had anticipated a midday attack, and advised the troops to fill their bellies well at breakfast; so they fought none the worse. The Persian cavalry advanced to within bowshot of the Roman cavalry on the wings and began to shoot; and a mass of foot-archers also pressed forward into the re-entrant and began firing clouds of arrows at the Roman infantry and at the light cavalry in the trench-angles. These foot-archers moved forward in parallel single files, with a single pace's interval between files. As soon as the man at the head of each file had fired one arrow he retired to the rear and then gradually came again to the head of the file; and by this means a steady stream of arrows was maintained. They greatly outnumbered our own archers, but they suffered from three great disadvantages. First, the stiff bows that Belisarius's recruits were using had a greater range than their own lighter ones; next, the wind was blowing from the west, so that their arrows lost speed and fell short; lastly, they were being fired at from the front and both flanks and were tightly enough packed to make the most random Roman shooting effective. The pressure of fresh troops from behind urged them farther forward than they wished, and though this brought them into closer range, they lost the more heavily. A half-hearted attempt on the part of their spearmen to capture two of the bridges simultaneously failed; the javelin men drove them off. Hut, an hour or two later, both sides having exhausted their missile weapons, there were desperate battles at the bridges all along the line with lance and spear, and attempts to cross the trenches with planks. Belisarius broke one dangerous thrust with dismounted cavalry — the right-hand squadron of Massagetic Huns, now recalled this side of the trench.