Onesicritus of Aegina

Diogenes Laertius, Book 6 ยง75

<blockquote>Cleomenes in his work entitled Concerning Pedagogues says that the friends of Diogenes wanted to ransom him, whereupon he called them simpletons; for, said he, lions are not the slaves of those who feed them, but rather those who feed them are at the mercy of the lions: for fear is the mark of the slave, whereas wild beasts make men afraid of them. The man had in fact a wonderful gift of persuasion, so that he could easily vanquish anyone he liked in argument. At all events a certain Onesicritus of Aegina is said to have sent to Athens the one of his two sons named Androsthenes, and he having become a pupil of Diogenes stayed there; the father then sent the other also, the aforesaid Philiscus, who was the elder, in search of him; but Philiscus also was detained in the same way.
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