The essence of the tragedy lies in the double fact of Apollo’s hostility to Œdipus and Jocasta and their ignorance of it. When Laius and Jocasta were young upon the throne of Thebes they prayed to Apollo to give them a son. The oracle at Delphi replied to Laius, “I will give thee a son, but it is doomed that thou leave the sunlight by the hands of thy child.” Thus the decree was launched.

Laius and Jocasta trembled at the doom, and considered how it might be averted. When their son was born, they took a cruel and desperate means to save its father’s life. Three days after his birth they handed over the babe to a herdsman, to be exposed on Mt. Kithairon. And first they pierced his heels, to ensure his death. So Jocasta, out of love for her husband and fear of the oracle, brought herself to a deed which poisoned all her life. Yet it was of no avail against fate. For the man who took her babe had pity on it; and meeting a friendly herdsman who was in the service of Polybus, king of Corinth, he gave the child to him. Polybus and his queen Merope were childless; and the herdsman believed that they would welcome the little foundling. He was not mistaken: calling him Œdipus from his swelled feet, they brought him up as their son.

All went well until the boy had grown into manhood. Then one day a young companion, heated with wine, flung out a taunt about his birth. Œdipus, fully believing himself to be the son of Polybus and Merope, went to them with the story. They chastised the offender, but their replies to Œdipus’ questions left a doubt of his parentage rankling in his mind. He determined to satisfy himself once for all by an appeal to Apollo; and he travelled to Delphi to inquire of the oracle in person. The reply was terrible, and, unlike most oracular utterances, seemed only too clear. He was doomed, it said, to slay his father and marry with his mother. But the most vital point, the names of his parents, was not revealed; and Œdipus, still believing them to be Polybus and Merope, vowed never again to set foot in Corinth while they were living. So he hoped to avoid his doom; and he set out alone, along the road to Bœotia, and Thebes.

Now it happened that just about that time Thebes was afflicted by a strange monster. It was the Sphinx, sent by Hera to prey upon the city. Sitting upon a neighbouring hill, she claimed the life of every man who could not read her riddle—“What is the creature which is two-footed, three-footed and four-footed; and weakest when it has most feet?” No one could find the answer; and Thebes daily paid the toll of life to the monster. The people were in despair, when Laius the king set out to seek counsel at Delphi. Thus the unknown father and son were hourly approaching each other from east and west. Laius was accompanied by only four attendants. When his party came to a narrow pass in Phokis, at a place where three roads met, a young man appeared in the path before them. The slaves of Laius were insolent, and the young man’s blood was hot. A quarrel ensued. Three of the attendants were struck down; and Laius himself, aiming at the stranger from his chariot, was killed by a single blow. Œdipus had unwittingly slain his father; and the first part of the curse had fallen.

The fourth attendant of Laius, the very man who had given away Jocasta’s babe years before to the Corinthian herdsman, fled for his life. Arrived at Thebes, he reported the death of the king. But he feared to tell the whole truth: he dared not admit that he and his fellows had been overcome by one man; and he gave out that Laius had been slain by a band of robbers.

Meantime, Œdipus continued his wanderings; and some time afterward he came to Thebes. He found the city still harassed by the Sphinx, who seized her victims daily from among the Theban people. He learned too that their king had been killed by robbers whilst on a journey; and that the old prophet Tiresias, who should have been able to advise the people at such a crisis, was helpless. The young stranger seized his opportunity. He faced the Sphinx and solved her riddle, triumphantly naming the creature of her question to be Man. Whereupon she flung herself down from the hill on which she was stationed; and the people of Thebes at last had rest from their tormentor. They hailed Œdipus with joy; and in their gratitude they named him king in succession to Laius.

But the new king could not put aside the queen who already occupied the throne. Indeed, by a custom of those old times, he could not rightly become the king unless she married him. He had proved himself to the Theban people brave and wise, a ruler to be desired. Consideration for her people inclined Jocasta to him, and besides, he seemed to her just and kind. But more than all, there hung about him, in his carriage or his manner, something which brought a fleeting memory of Laius, and warmed her heart to him. So she consented that he should be her husband.

The curse on Œdipus was now complete. In perfect innocence, and though he had striven to keep his hands clean from the horror, he had slain his father and married with his mother. Yet no shadow of the truth fell on him. There were in Thebes two persons to whom it was known, or partly known. One was that slave born in Laius’s household who had given the infant prince to the herdsman from Corinth; and who had fled for his life when his master was killed at the cross-roads in Phokis. The other was the blind old prophet Tiresias. But neither spoke of what they knew. The slave kept silence from loyalty; and coming to the queen soon after her marriage, he besought her earnestly to send him back to serve in outland parts. Tiresias was merely prudent; and thought it best to bide the time of the god.

For many years no sign came. Jocasta and Œdipus, loving each other and beloved by their people, reigned happily in Thebes; Creon, Jocasta’s brother, sharing equally in the honour which was paid to them. Four children were born to the king and queen: two sons, named Eteocles and Polynices; and two daughters, Antigone and Ismene. Life flowed so smoothly now that painful memories grew faint. Œdipus had almost forgotten the menace that rang in his ears at Delphi twelve years before; and Jocasta, though she would never forget that early act of cruelty, was not haunted so persistently now by the thought of her first-born. It seemed almost that Apollo had relented; that having fulfilled the letter of the doom, he had taken pity on the victims, and would leave them in happy ignorance. But he, too, was only waiting for a fitting moment—till Thebes should be most flourishing and Œdipus should have reached the top of fame. Then the blow fell. A sudden plague was sent upon the city, which ravaged all life like a blight. Flocks sickened; the harvest failed; and human creatures died in thousands, while Œdipus looked on, sore at heart for their misery, but powerless to help.

At this point of the story, Sophocles has opened the Œdipus, King of Thebes. The scene is before the royal palace, where a crowd of suppliants has gathered to implore the aid of the king. Œdipus comes out in person to receive them, and listens patiently while the old priest petitions him on their behalf. They have pathetic faith in him. There can be no doubt that he has power to succour them, for did he not of old save Thebes from the Sphinx? Perhaps too there is a touch of deeper meaning in their act, a hint of that duty laid on early kings, to die for their people in case of need. They come to lay on him the burden of the whole land’s sorrow. Œdipus answers them pityingly.