But just as among the elements of the universe, according to Empedocles, love and hate produce mutual dissension and war, particularly among those elements which touch or lie near one another, so the continuous wars which the successors of Alexander waged against one another were aggravated and more inflamed in some cases by the close proximity of interests and territories, as at this time in the case of Antigonus and Ptolemy. Antigonus himself was tarrying in Phrygia, and hearing there that Ptolemy had crossed over from Cyprus and was ravaging Syria and reducing or turning from their allegiance its cities, he sent against him his son Demetrius, who was only twenty-two years of age, and was then for the first time engaging with sole command in an expedition where great interests were at stake. But since he was young and inexperienced, and had for his adversary a man trained in the training-school of Alexander who had independently waged many great contests, he met with utter defeat near the city of Gaza, where eight thousand of his men were taken prisoners and five thousand were slain. He lost also his tent, his money, and in a word, all his, personal effects. But Ptolemy sent these back to him, together with his friends, accompanying them with the considerate and humane message that their warfare must not be waged for all things alike, but only for glory and dominion. Demetrius accepted the kindness, and prayed the gods that he might not long be indebted to Ptolemy for it, but might speedily make him a like return. And he took his disaster, not like a stripling thwarted at the outset of an undertaking, but like a sensible general acquainted with reverses of fortune, and busied himself with the levying of men and the preparation of arms, while he kept the cities well in hand and practised his new recruits.