Suggested translation: "Letters," Plato in Twelve Volumes, vol. 7, trans. R. G. Bury, Cambridge, MA: Harvard University Press, 1966.
Excerpt:
Plato to Dionysius wishes well-doing.
After I had spent so long a time with you and was trusted above all others in my administration of your government, while you were enjoying the benefits I was enduring the slanders, grievous as they were. For I knew that men would not believe that any of your more brutal acts were done with my consent, seeing that I have for my witnesses all those who take a part in your government, many of whom I have helped in their times of trial and saved them from no small damage. But after I had oftentimes kept guard over your City as sole Dictator, I was dismissed with more ignominy than a beggar would deserve who had stayed with you for so long a time, were you to pack him off and order him to sail away.