Jo Walton’s The Just City and its sequel, The Philosopher Kings, posit a world in which the ancient Greek pantheon of gods is real, and exists outside of time. Athena is therefore able to establish a Utopian city based on Plato’s Republic centuries before Plato ever writes it, populated by mortals (and one incarnate god) from a wide swath of history.
But as grateful as the Masters and Children of the city are to have a bona fide goddess on their side, perhaps they’d better brush up on their mythological history. Because the Greek gods? Nothing but trouble.