Prince Llywelyn of Gwynedd had a favorite dog named Gelert, a fearless hunting dog and loyal companion, said to be a gift from King John of England.
One day, Llywelyn left his infant son in the care of a nurse and a servant while he went hunting with his wife. The nurse and servant, however, went for a walk in the mountains, leaving the baby alone.
During the hunt, Llywelyn noticed Gelert was missing. Believing the dog must have returned to the lodge, he called off the hunt and headed home.
As the hunting party arrived, Gelert ran out of the lodge towards his master, covered in blood but wagging his tail. The princess, calling for her child, fainted. Llywelyn rushed inside to find the cradle overturned, bloodstained bedclothes scattered on the floor, and no sign of his son.
Blinded by anger and grief, Llywelyn drew his sword and killed Gelert. As the dog died, its whimpers were answered by a baby's cry from behind the overturned cradle. Llywelyn moved the cradle to find his son unharmed, next to the bloody body of a huge wolf. Gelert had killed the wolf while defending the child.
Overcome with remorse, Llywelyn never spoke again. He buried Gelert in a nearby meadow and marked the grave with a cairn of stones, forever haunted by the memory.
The village of Beddgelert (meaning "Gelert's Grave") in North West Wales is believed to be named after this legend, though there is no historical evidence for the story.