Letters 94.65

What drew him into Africa, into the North, against Mithridates, into Armenia and all the corners of Asia? Assuredly it was his boundless desire to grow bigger; for only in his own eyes was he not great enough. And what impelled Gaius Caesar to the combined ruin of himself and of the state? Renown, self-seeking, and the setting no limit to pre-eminence over all other men. He could not allow a single person to outrank him, although the state allowed two men to stand at its head.

Seneca, Letters to Lucilius 94.65, translated by Richard Mott Gummere