<blockquote>Chap. XXXIII. Of Plato and Diogenes. Diogenes being present at a discourse of Plato's, would not mind it, whereat Plato angry said, “Thou Dog, why mindest thou not? Diogenes unmoved, answered, “Yet I never return to the place where I was sold, as Dogs doe” ; alluding to Plato's Voyage to Sicily.
It is reported that Plato used to say of Diogenes, “This man is Socrates mad.”
Source: Thomas Stanley, translator (1665) Claudius Aelianus His Various History</blockquote>