Plutarch, Pyrrhus
Bernadotte Perrin, Ed.

4. When he had reached the age of seventeen years¹ and was thought to be firmly seated on his throne, it came to pass that he went on a journey, when one of the sons of Glaucias, with whom he had been reared, was married. Once more, then, the Molossians banded together, drove out his friends, plundered his property, and put themselves under Neoptolemus.² [2] Pyrrhus, thus stripped of his realm and rendered destitute of all things, joined himself to Demetrius the son of Antigonus, who had his sister Deïdameia to wife. She, while she was still a girl, had been nominally given in marriage to Alexander, Roxana's son; but their affairs miscarried, and when she was of age Demetrius married her.³ In the great battle which all the kings fought at Ipsus⁴ Pyrrhus was present, and took part with Demetrius, though still a stripling. [3] He routed the enemy opposed to him, and made a brilliant display of valour among the combatants. Moreover, though Demetrius lost the day, Pyrrhus did not abandon him, but kept guard over his cities in Greece which were entrusted to him,⁵ and when Demetrius made peace with Ptolemy, sailed to Egypt as hostage for him. [4] Here, both in hunting and in bodily exercises, he gave Ptolemy proof of his prowess and endurance, and seeing that among the wives of Ptolemy it was Berenicé who had the greatest influence and was foremost in virtue and understanding, he paid especial court to her. He was adept at turning to his own advantage the favour of his superiors, just as he was inclined to look down upon his inferiors, and since he was orderly and restrained in his ways of living, he was selected from among many young princes as a husband for Antigone, one of the daughters of Berenicé, whom she had by Philip⁶ before her marriage with Ptolemy.