Life and Times
Mithaecus lived around 400 BC. He is probably the first cookery writer in history, or more fairly, that we know of, though we have only one recipe from him (quoted in “Athenaeus.”)
Mithaecus was a Greek living in the Greek colony of Sicily long before Italians or even Romans had padded onto the scene. The city of Syracuse, Sicily was very prosperous, enjoying a standard of living that Greeks back in the homeland with its poorer soil could only dream of. This environment of prosperity provided context for a culture of food appreciation to evolve. Cooks from Syracuse would be recruited by the wealthy back in Greek to come work for them.
Plato mentions Mithaecus, though not particularly favourably — Plato mocked the idea that people such as Mithaecus who had contributed to an appreciation of fine dining could be considered as having contributed anything to civilisation . And Socrates felt that people such as Mithaecus (Mithaecus’s name was well enough known for Socrates to quote with no further explanation) actually contributed to the physical decline of a people.
Mithaecus probably spoke the dialect of Greece called “Doric”, which was the language of Sparta. It’s thought this because at one point, he came to Sparta and tried to work there, but was expelled. The kind of enjoyment of food that he espoused was seen as too decadent for Sparta (as related by Maximus of Tyre: whether the story is true is another matter.)
Mithaecus is cited by Athenaeus in his “Deipnosophists” (three times), and it’s thanks to Athenaeus that we have that one remaining recipe, which Athenaeus quotes. This makes it the first recipe that we know of to date (2007) that is actually attributed to someone. 
That being said, it’s not a particularly long recipe:
Tainia : gut, discard the head, rinse and fillet; add cheese and olive oil.
 Plato says, “Mithaikos who wrote the Sicilian cookery book.” Mithaecus’s book must have been obtainable in Athens for Plato to have seen it or at least have known about it, or Plato found out about it on one of his trips to Sicily.
 We know of poets in Syracuse who before Mithaecus had written about food — but they talked about it, rather than giving recipes.
 Tainia, or Cepola rubescens, is what we now call in English “Serpent Fish.”
Shaun Hill & John Wilkins. Mithaikos and Other Greek Cooks. From Proceedings of the Oxford Symposium on Food in Antiquity – Cooks and Other People 1995 pp. 144-8.