According to the Greek historian Herodotus, the fables were invented by a slave named Aesop, who lived in Ancient Greece during the 5th century BC. While some suggested that Aesop did not actually exist, and that the fables attributed to him are folktales of unknown origins, Aesop was indeed mentioned in several other Ancient Greek works – Aristophanes, in his comedy "The Wasps," represented the protagonist Philocleon as having learnt the "absurdities" of Aesop from conversation at banquets; Plato wrote in "Phaedo" that Socrates whiled away his jail time turning some of Aesop's fables "which he knew" into verses; Demetrius of Phalerum compiled the fables into a set of eleven books (Lopson Aisopeion sunagogai), which have been lost, for the use of orators. There was also an edition in elegiac verse by an anonymous author, which was often cited in the Suda.