Amphion and Zethus (also Zethos), in ancient Greek mythology, were the twin sons of Zeus by Antiope. They are important characters in one of the two founding myths of the city of Thebes, because they constructed the city's walls.
Amphion and Zethus were the sons of Antiope, who fled in shame to Sicyon after Zeus raped her, and married King Epopeus there. However, either Nycteus or Lycus attacked Sicyon in order to carry her back to Thebes and punish her. On the way back, she gave birth to the twins and was forced to expose them on Mount Cithaeron. Lycus gave her to his wife, Dirce, who treated her very cruelly for many years.
Antiope eventually escaped and found her sons living near Mount Cithaeron. After they were convinced that she was their mother, they killed Dirce by tying her to the horns of a bull, gathered an army, and conquered Thebes, becoming its joint rulers.
Amphion became a great singer and musician after Hermes taught him to play and gave him a golden lyre. Zethus became a hunter and herdsman, with a great interest in cattle breeding. They built the walls around the Cadmea, the citadel of Thebes. While Zethus struggled to carry his stones, Amphion played his lyre and his stones followed after him and gently glided into place.
Amphion married Niobe, the daughter of Tantalus, the Lydian king. Because of this, he learned to play his lyre in the Lydian mode and added three strings to it. Zethus married Thebe, after whom the city of Thebes was named.
Zethus had only one son, who died through a mistake of his mother Thebe, causing Zethus to kill himself. In the Odyssey, however, Zethus's wife is called a daughter of Pandareus in book 19, who killed her son Itylos in a fit of madness and became a nightingale.
Afther the deaths of Amphion and Zethus, Laius returned to Thebes and became king.