Who informs Oedipus that he is adopted?

The messenger from Corinth plays a pivotal role in revealing to Oedipus that he is adopted. Throughout the play, Oedipus is searching for the truth about his parentage, and it is this messenger who comes from Corinth and brings the crucial information that Oedipus was not born to the royal couple of Thebes but was instead adopted. This revelation is significant because it sets into motion the tragic unfolding of events; Oedipus has spent much of his life believing he was the biological son of Polybus and Merope, the king and queen of Corinth.

The messenger further confirms Oedipus's origin by explaining how he came to be adopted by them, recounting the story of how he was found as an infant. This information shifts Oedipus's understanding of his identity and propels the dramatic irony of the play, as the audience knows the implications of his true origins long before he does. Thus, the messenger's role is critical in Oedipus's journey toward self-discovery and the eventual tragic realization of his fate.