Setanta is the name that Cuchulain, a mythological Irish hero, had when he was a boy. Frank McCourt first learns the story of Cuchulain, or Setanta, from his father while the family is living in New York. According to Malachy McCourt, Setanta grew up in Ireland where he himself lived, in County Antrim. Setanta used to like to play with a stick and a ball, and one day he hit the ball, which went into the mouth of a big dog belonging to a man named Culain, and choked him. Culain was angry, and asked Setanta, "what am I to do now without my big dog to guard my house and my wife and my ten small children as well as numerous pigs, hens, and sheep?"
Repentant, Setanta offered to guard Culain's house with his stick and ball in place of the dog. Setanta changed his name to Cuchulain, "the Hound of Culain". He guarded Culain's house and the surrounding regions and became a great hero. His reknown spread beyond the immediate vicinity, and he became known as the "Hound of Ulster".
Tales about Cuchulain's exploits are legendary in Irish folklore. Malachy McCourt tells Frankie that Cuchulain is a greater hero than the Greeks' Hercules or Achilles, and the British King Arthur. Frankie loves the story his father has told him, and decides that it is his story alone, and not to be told to his little brother Malachy nor the other children in the neighborhood (Chapter 1).