My father and I just finished The Philosopher Kings, book #2 of the Thessaly Trilogy, by Jo Walton - a series of that rarest of genres, Historical Fantasy.
Who needs one Plato's Republic when you can have thirteen? Who knows what happens when they quarrel, all having different interpretations of Plato and religion? How will their deeds fit inside Fate and Necessity?
(What can an incarnate Olympian learn of mortality?)
We learned the answers to the first two through pursuing arete (hehehe). Now we just have to see about the third.
Honestly I have seldom read a book that so confounded my ability to make predictions, despite my knowledge of Greek mythology (with one exception).