Oedipus Rex by Sophocles, what Led to His Downfall?

"There is no man blessed amongst us. All the works of man are known and every
soul is tried," sings the chorus at the beginning of Oedipus Rex. After answering the riddle of man, Oedipus becomes the foremost of living men and takes his turn on the top of the wheel. Oedipus believes, "it is better to rule over man than over a wasted place; since, a walled township is nothing if it is empty and has no man within it." But, what he does not realize is that very soon he will have fallen to the bottom. Oedipus believes three people are out to get him: Tiresias, Creon, and Jocasta. …