In The Oedipus Cycle, three shepherds play a major role in the propecy of Oedipus. According to the prophecy, Oedipus will kill his father and sleep with his mother. Oedipus's father, Laius, in an attempt to avert the crisis, cuffed Oedipus's ankles and gave him to his wife Iocasta to leave him in the mountains to die.
The first shepherd receives Oedipus, but he displayed great sympathy for him. He saved Oedipus's life and passed him on to a second shepherd. This second shepherd took care of him as well, until he finally passed it on the third shepherd. He gives Oedipus to Polybus and Merope, who adopt him as their son.
During the incident at the crossroads with Laius's murder, the third shepherd turns out to be the sole living witness to the murder scene. Oedipus brings him in to interrogate him, but the shepherd refuses to speak. It takes the threat of an execution to get the shepherd to reveal his account; he asserts that Laius had indeed been killed. In addition, he informs Oedipus that he was adopted, a fact that proves disastrous, leading to Iocasta's death and Oedipus's loss of sight.