Phthia (Greek: Φθία or Φθίη; transliterations: Fthii (modern), Phthíē (ancient)) in ancient Greece was the southernmost region of ancient Thessaly, on both sides of Othrys Mountain. It was the homeland of the Myrmidones tribe, who took part in the Trojan War under Achilles.
CRITO: It has not arrived yet, but it will, I believe, arrive today, according to a message some men brought from Sunium, where they left it. This makes it obvious that it will come today, and that your life must end tomorrow.
SOCRATES: ...I do not think it will arrive on this coming day, but on the next. I take to witness of this a dream I had a little earlier during this night...I thought that a beautiful and comely woman dressed in white approached me. She called me and said: "Socrates, may you arrive at fertile Phthia on the third day."
The reference to Phthia is itself a reference to Homer's Iliad (ix.363), when Achilles, upset at having his war-prize, Briseis, taken by Agamemnon, rejects Agamemnon's conciliatory presents and threatens to set sail in the morning; he says that with good weather he might arrive on the third day "in fertile Phthia" — his home. In Plato's work, Socrates tells his friend, Crito, that he expects to be executed the day after next (the Greeks counted inclusively, so the "third day" counts today as the first, tomorrow as the second, and the day after as the third), interpreting the dream to mean that he will arrive at his new home one day later than Crito expects.
Phthia is the setting of Euripides' play Andromache , which takes place after the Trojan War, when Achilles' son Neoptolemus (in some translations named Pyrrhus) has taken the widow of the Trojan hero Hector as a slave.
Professor C.J. Mackie notes the linguistic association of "Phthia" with the Greek word phthisis, meaning "consumption," "decline" or "wasting away" and the connection of the place name with a withering death. (In English, the word has been used as a synonym for tuberculosis.) Mackie thus notes a wordplay in Homer that associates Achilles' home with such a withering death.<Mackie, C.J., "Homeric Phthia," Colby Quarterly, Volume 38, no.2, June 2002, p.163-173.> 
- Thucydides and Pindar: historical narrative and the world of Epinikian poetry By Simon Hornblower Page 170 ISBN 0-19-924919-9
- translated by Benjamin Jowett on the MIT website.
- Cooper, John M., ed. (1997). Plato: Complete Works. Associate editor, D. S. Hutchinson. Translation of Crito by G. M. A. Grube. Indianapolis/Cambridge: Hackett. p. 39. ISBN 0-87220-349-2.