Rural life builds the body which luxury destroys

"I realize that in the first ages of the Republic, the Romans always raised their armies in the city itself, but this was at a time when there were no pleasures, no luxuries to enervate them. The Tiber was then their only bath, and in it they refreshed themselves after their exercises and fatigues in the field by swimming. In those days the same man was both soldier and farmer, but a farmer who, when occasion arose, laid aside his tools and put on the sword. The truth of this is confirmed by the instance of Quintius Cincinnatus, who was following the plow when they came to offer him the dictatorship. The chief strength of our armies, then, should be recruited from the country. For it is certain that the less a man is acquainted with the sweets of life, the less reason he has to be afraid of death."

Vegetius. Epitoma rei militaris. [Translated by Lieutenant John Clarke]

"I can not too strongly insist upon the need of a return to the method of old times. Our ancestors, when about to build a town or an army post, sacrificed some of the cattle that were wont to feed on the site proposed and examined their livers. If the livers of the first victims were dark-coloured or abnormal, they sacrificed others, to see whether the fault was due to disease or their food. They never began to build defensive works in a place until after they had made many such trials and satisfied themselves that good water and food had made the liver sound and firm. If they continued to find it abnormal, they argued from this that the food and water supply found in such a place would be just as unhealthy for man, and so they moved away and changed to another neighbourhood, healthfulness being their chief object."

Vitruvius. Architecture.