Plato Epistles 11

[358] 358d
  Plato to Laodamas wishes well-doing.
  I wrote to you before that in view of all that you say it is of great importance that you yourself should come to Athens . But since you say that this is impossible, the second best course would have been that I, if possible, or Socrates should go to you, as in fact you said in your letter. At present, however, Socrates 358e is laid up with an attack of strangury; while if I were to go there, it would be humiliating if I failed to succeed in the task for which you are inviting me. But I myself have no great hopes of success (as to my reasons for this, another long letter would be required to explain them in full), and moreover, because of my age, I am not physically fit to go wandering about and to run such risks as one encounters both by sea and land; and at present there is nothing but danger for travellers everywhere. ¹

[359] 359 359a I am able, however, to give you and the settlers advice which may seem to be, as Hesiod ² says, For they are mistaken if they believe that a constitution could ever be well established by any kind of legislation whatsoever without the existence of some authority ³ in the State which supervises the daily life both of slaves and freemen, to see that it is both temperate and manly. And this condition might be secured if you already possess men who are worthy of such authority. 359b If, however, you require someone to train them, you do not, in my opinion, possess either the trainer or the pupils to be trained; so it only remains for you to pray to the gods. ⁴ For, in truth, the earlier States also were mostly organized in this way; and they came to have a good constitution at a later date, as a result of their being confronted with grave troubles, either through war or other difficulties, whenever there arose in their midst at such a crisis a man of noble character in possession of great power.
  So it is both right and necessary that you should at first be eager for these results, 359c but also that you should conceive of them in the way I suggest, and not be so foolish as to suppose that you will readily accomplish anything. Good-fortune attend you!