In the Oedipus Tyrannus, Sophocles goes back to the central crisis of
the Theban story. And again he fixes our attention, not so much on the
fortunes of the city, or of the reigning house, as on the man Oedipus,
his glory and his fall.--

'O mirror of our fickle state
Since man on earth unparalleled!
The rarer thy example stands,
By how much from the top of wondrous glory,
Strongest of mortal men,
To lowest pitch of abject fortune thou art fallen[2].

The horror and the pity of it are both enhanced by the character of
Oedipus--his essential innocence, his affectionateness, his
uncalculating benevolence and public spirit;--while his impetuosity
and passionateness make the sequel less incredible.

The essential innocence of Oedipus, which survives the ruin of his
hopes in this world, supplies the chief motive of the Oedipus at
Colonos. This drama, which Sophocles is said to have written late in
life, is in many ways contrasted with the former Oedipus. It begins
with pity and horror, and ends with peace. It is only in part founded
on Epic tradition, the main incident belonging apparently to the local
mythology of the poet's birthplace. It also implies a later stage of
ethical reflection, and in this respect resembles the Philoctetes; it
depends more on lyrical and melodramatic effects, and allows more room
for collateral and subsidiary motives than any other of the seven. Yet
in its principal theme, the vindication or redemption of an
essentially noble spirit from the consequences of error, it repeats a
note which had been struck much earlier in the Aias with great force,