Which character is known for unknowingly committing patricide and marrying his mother?

The character associated with the act of unknowingly committing patricide and marrying his mother is Oedipus. This tragic figure from Greek mythology is best known from Sophocles' play "Oedipus Rex," in which a prophecy foretells that he will kill his father and marry his mother. Unaware of his true parentage, Oedipus fulfills this prophecy by killing his father, Laius, in a chance encounter and subsequently marrying his mother, Jocasta, after solving the riddle of the Sphinx and becoming the king of Thebes.

This tale emphasizes themes of fate, free will, and tragic irony, as Oedipus' attempts to avoid the prophecy lead him directly to its fulfillment. The other characters listed, Theseus, Achilles, and Hector, are significant figures in Greek mythology and literature but do not embody the specific actions of patricide and incestuous marriage associated with Oedipus' story.