Plutarch Caesar 17

[1] Such spirit and ambition Caesar himself created and cultivated in his men, in the first place, because he showed, by his unsparing bestowal of rewards and honours, that he was not amassing wealth from his wars for his own luxury or for any life of ease, but that he treasured it up carefully as a common prize for deeds of valour, and had no greater share in the wealth than he offered to the deserving among his soldiers; and in the second place, by willingly undergoing every danger and refusing no toil.

[2] Now, at his love of danger his men were not astonished, knowing his ambition; but that he should undergo toils beyond his body’s apparent power of endurance amazed them, because he was of a spare habit, had a soft and white skin, suffered from distemper in the head, and was subject to epileptic fits, a trouble which first attacked him, we are told, in Corduba.

[3] Nevertheless, he did not make his feeble health an excuse for soft living, but rather his military service a cure for his feeble health, since by wearisome journeys, simple diet, continuously sleeping in the open air, and enduring hardships, he fought off his trouble and kept his body strong against its attacks. Most of his sleep, at least, he got in cars or litters, making his rest conduce to action, and in the day-time he would have himself conveyed to garrisons, cities, or camps one slave who was accustomed to write from dictation as he travelled sitting by his side, and one soldier standing behind him with a sword.

[4] And he drove so rapidly that, on his first journey from Rome to Gaul, he reached the Rhone in seven days.
  Horsemanship, moreover, had been easy for him from boyhood; for he was wont to put his hands behind his back and, holding them closely there, to ride his horse at full speed. And in the Gallic campaigns he practised dictating letters on horseback and keeping two scribes at once busy, or, as Oppius says, even more.

[5] We are told, moreover, that Caesar was the first to devise intercourse with his friends by letter, since he could not wait for personal interviews on urgent matters owing to the multitude of his occupations and the great size of the city. Of his indifference in regard to his diet the following circumstance also is brought in proof. When the host who was entertaining him in Mediolanum, Valerius Leo, served up asparagus dressed with myrrh instead of olive oil, Caesar ate of it without ado, and rebuked his friends when they showed displeasure.

[6] Surely, said he, it were enough not to eat what you don’t like; but he who finds fault with ill-breeding like this is ill-bred himself. Once, too, upon a journey, he and his followers were driven by a storm into a poor man’s hut, and when he found that it consisted of one room only, and that one barely able to accommodate a single person, he said to his friends that honours must be yielded to the strongest, but necessities to the weakest, and bade Oppius lie down there, while he himself with the rest of his company slept in the porch.