Demetrius (19.6-20.1)

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.

Nay, he was actually thought to be a better general in preparing than in employing a force, for he wished everything to be at hand in abundance for his needs, and could never be satisfied with the largeness of his undertakings in building ships and engines of war, or in gazing at them with great delight. For he had good natural parts and was given to speculation, and did not apply his ingenuity to things that would afford useless pleasure or diversion, like other kings who played on the flute, or painted, or chased metals.