Strabon, Geographika XV 3, 18:

From five years of age to twenty-four they are trained to use the bow, to throw the javelin, to ride horseback, and to speak the truth; and they use as teachers of science their wisest men, who also interweave their teachings with a mythical element, thus reducing that element to a useful purpose, and rehearse both with song and without song the deeds both of the gods and of the noblest men.

And these teachers wake the boys up before dawn by the sound of brazen instruments, and assemble them in one place, as though for arming themselves or for a hunt; and then they divide the boys into companies of fifty, appoint one of the sons of the king or of a satrap as leader of each company, and order them to follow their leader in a race, having marked off a distance of thirty or forty stadia.

They require them also to give an account of each lesson, at the same time training them in loud speaking and in breathing, and in the use of their lungs, and also training them to endure heat and cold and rains, and to cross torrential streams in such a way as to keep both armour and clothing dry, and also to tend flocks and live outdoors all night and eat wild fruits, such as pistachio nuts, acorns, and wild pears. These are called Cardaces, since they live on thievery, for “carda” [κάρδα] means the manly and warlike spirit. (1)
Their daily food after their gymnastic exercises consists of bread, barely-cake, cardamum, grains of salt, and roasted or boiled meat; but their drink is water.

They hunt by throwing spears from horseback, and with bows and slings; and late in the afternoon they are trained in the planting of trees and in the cutting and gathering of roots (2) and in making weapons and in the art of making linen cloths and hunters’ nets. The boys do not touch the meat of wild animals, though it is the custom to bring them home.

Prizes are offered by the king for victory in running and in the four other contests of the pentathla (3). The boys are adorned with gold, since the people hold in honour the fiery appearance of that metal; and on this account, in honour of its fiery appearance, they do not apply gold, just as they don not apply fire, to a dead body.

Strabo: Geography VII. Ed. by Horace Leonard Jones. Cambridge (Mass.) / London ⁸2006, pp. 178-181)

(1) Bei diesem Satz kann es sich um eine Interpolation handeln.
(2) für medizinische Zwecke
(3) Die Pentathla waren: Springen, Diskuswerfen, Laufen, Ringen und Speerwerfen oder Boxen.