VI. Antigonus when he heard of the defeat remarked that Ptolemy had conquered beardless boys, but that he would have to fight his next battle with grown men. He yielded however to his son's entreaty to be allowed to repair his fault by himself, and, as he did not wish to damp his spirits, left him in sole command. Soon after this Killes, Ptolemy's lieutenant, arrived in Syria with a large force, meaning to chase Demetrius, whom he supposed to be disheartened by his defeat, quite out of Syria. But Demetrius by a sudden attack surprised his army and struck it with panic. He captured the enemy's camp and their general, and took eight thousand prisoners and a great quantity of booty. He was overjoyed at this, not because he meant to keep what he had won, but to give it back, and did not so much value the glory and wealth which he had gained as the opportunity now offered him for repaying the courtesy of Ptolemy. He did not presume to do this on his own responsibility, but wrote first to his father. On receiving permission from him to deal as he pleased with the fruits of his victory, he gave costly presents to Killes and his friends, and sent them back to Ptolemy. This battle forced Ptolemy to retire from Syria, and brought Antigonus from Kelænæ rejoicing at the victory and eager to see his son. VII. After this Demetrius was sent to subdue the Nabathean Arabs, in performing which service he incurred great danger by journeying through waterless deserts; but his intrepid courage overawed the barbarians, and he returned loaded with plunder, having captured seven hundred camels. Seleukus had once lost his capital city, Babylon, which Antigonus took from him; but he had since recovered it by his own arms, and at this time was marching with an army to attempt the conquest of the nations bordering upon India, and the provinces near mount Caucasus. Demetrius, hoping that he might find Mesopotamia in a defenceless condition, suddenly crossed the Euphrates, took Babylon by surprise, and made himself master of one of its two citadels, driving out the garrison placed there by Seleukus. Demetrius placed seven thousand of his own troops in the citadel, ordered his troops to enrich themselves by the plunder of the surrounding country, and then returned to the sea-coast, leaving Seleukus more firmly established on his throne than before; for by plundering the country he seemed to admit that he had no claim to it. As Ptolemy was now besieging Halikarnassus, he quickly marched thither and succeeded in saving the city.