Plutarch Demetrius 19

[1] Antigonus, elated by the achievements of Demetrius at Cyprus, at once ¹ made an expedition against Ptolemy; he himself led his forces by land, while Demetrius with a great fleet cooperated with him by sea. How the enterprise was to issue, Medius, a friend of Antigonus, was warned by a vision in his sleep.

[2] He dreamed, namely, that Antigonus himself, with his whole army, was competing in a race over the course and back; he ran vigorously and swiftly at first, then, little by little, his strength failed him; and at last, after he had made the turn, he became weak, breathed heavily, and with difficulty made the finish. And conformably to the vision, Antigonus himself encountered many difficulties by land, and since Demetrius also encountered a great storm and a heavy sea and was cast upon a rough coast which had no harbours, losing many of his ships, he returned without accomplishing anything.

[3]
  Antigonus was at this time almost eighty years old, and his great size and weight, even more than his old age, made it difficult for him to conduct expeditions. He therefore made use of his son instead, whose good fortune and experience now enabled him to conduct the greatest affairs successfully, and whose luxuries, extravagances, and revelries gave his father no concern. For although in time of peace Demetrius plunged deep into these excesses and devoted his leisure to his pleasures without restraint and intemperately, yet in time of war he was as sober as those who were abstemious by nature.

[4] And we are told that once, after Lamia was known of all men to be in complete control of Demetrius, he came home from abroad and greeted his father with a kiss, whereupon Antigonus said with a laugh, One would think, my son, that thou wert kissing Lamia. Again, on another occasion, when Demetrius had been at his revels for several days, and excused his absence by saying that he was troubled with a flux, So I learned, said Antigonus, but was it Thasian or Chian wine that flowed?

[5] And again, learning that his son was sick, Antigonus was going to see him, and met a certain beauty at his door; he went in, however, sat down by his son, and felt his pulse. The fever has left me now, said Demetrius. No doubt, my boy, said Antigonus, I met it just now at the door as it was going away.

[6] These failings of Demetrius were treated with such lenity by his father because the young man was so efficient otherwise. The Scythians, in the midst of their drinking and carousing, twang their bow-strings, as though summoning back their courage when it is dissolved in pleasure; but Demetrius, giving himself up completely, now to pleasure, and now to duty, and keeping the one completely separate from the other, was no less formidable in his preparations for war.