His daughter Arsinoe married Lysimachus in his old age, and urged him against his son, Agathocles, the husband of her own sister.  She afterwards married her half-brother, Ptolemy Ceraunus; and lastly became the wife of her brother Philadelphus.  Argzeus, the youngest son of Ptolemy, was put to death by Philadelphus on a charge of treason.  Of his youngest daughter Philotera we know nothing, except that her brother Philadelphus afterwards named a city on the coast of the Red Sea after her.

After the last battle with Demetrius, Ptolemy had regained the island of Cyprus and Cole-Syria, including Judaea; and his throne became stronger as his life drew to an end.  With a wisdom rare in kings and conquerors, he had never let his ambition pass his means; he never aimed at universal power; and he was led, both by his kind feelings and wise policy, to befriend all those states which, like his own, were threatened by that mad ambition in others.

His history of Alexander’s wars is lost, and we therefore cannot judge of his merits as an author; but we may still point out with pleasure how much his people gained from his love of letters; though indeed we do not need the example of Ptolemy to show that learning and philosophy are as much in place, and find as wide a field of usefulness, in governing a kingdom as in the employments of the teacher, the lawyer, or the physician, who so often claim them as their own.

His last public act, in the thirty-eighth year of his reign, was ordered by the same forbearance which had governed every part of his life.  Feeling the weight of years press heavily upon him, that he was less able than formerly to bear the duties of his office, and wishing to see his son firmly seated on the throne, he laid aside his diadem and his title, and, without consulting either the army or the capital, proclaimed Ptolemy, his son by Berenice, king, and contented himself with the modest rank of somatophylax, or satrap, to his successor.  He had used his power so justly that he was not afraid to lay it down; and he has taught us how little of true greatness there is in rank by showing how much more there is in resigning it.  This is perhaps the most successful instance known of a king, who had been used to be obeyed by armies and by nations, willingly giving up his power when he found his bodily strength no longer equal to it.  Ptolemy Soter had the happiness of having a son willing to follow in the track which he had laid down for him, and of living to see the wisdom of his own laws proved by the well-being of the kingdom under his son and successor.