What we know of Diogenes the Cynic (there are actually several philosophers called Diogenes, some of which are quite important) comes out of Diogenes Laertius, a Second Sophistic writer, and scattered quotations and quoted traditions in other authors. Diogenes Laertius makes up the vast majority of the surviving tradition on Diogenes the Cynic and, typically among Second Sophistic authors, he gives a highly romanticized, almost mythical presentation of the philosophers that he talks about. Like Plutarch he likes anecdotes and apocryphal traditions. Diogenes Laertius does refer to other authors (and sometimes to Diogenes the Cynic's own writings) as sources, but we rarely know whether these authors are particularly accurate, and the majority of his text is unsourced and is made up of clearly apocryphal stories. This is true for all of the philosophers Diogenes Laertius writes about, but Diogenes the Cynic is especially problematic--Diogenes, like Socrates, was rarely understood by his contemporaries and, like Socrates, he rapidly became the stuff of legend even within his own lifetime. Therefore Diogenes Laertius and our other sources present a Diogenes whose life intertwines fact and fiction almost inseparably. We can be reasonably sure of broad things, like when and why he left Sinope, but specific events and quotations are at best a hazy business. In some cases, like Diogenes' remarks to Alexander, we have multiple accounts (from Plutarch and Diogenes Laertius, and as early as Cicero), which indicates that at the very least it was a tradition that Diogenes said something like that, but all of our sources present this as an apocryphal tale, so we really don't know if it was just a story that was told or what. This is typical, both in Diogenes Laertius in general and for Diogenes the Cynic especially. We know about Diogenes' philosophical beliefs (although the Cynics didn't actually practice what Diogenes seems to have preached, being more influenced by Crates) and we know the broad strokes of Diogenes' life, but little else