A <u>theme</u> can be defined as the main idea or underlying message the author tries to convey in his literary work. This abstract idea conveyed by the author emerges from the treatment of a given subject throughout the literary piece.
Taking into account this definition, we may say that the statement that is a theme is true friends remain loyal despite hardship.
In the fourth episode, the Servant actually eagerly answers to Oedipus's questioning about his heritage - that he was abandoned by his parents and that he is that same baby he had been asking around about.
