The Gordian Knot is the earliest reference to a string puzzle. In Greek mythology, a Phrygian peasant called Gordius, the father of Minos (see mazes), became king because he was first to arrive in town after an oracle commanded the Phrygians to select as ruler the first person to drive into the public square in a wagon. In gratitude, Gordius dedicated his wagon to Zeus and placed it in the temple grove, tying the wagon pole to the yoke with a rope of bark. The knot was so intricately entwined that no one could undo it. A saying developed that whoever succeeded in untying the knot would become ruler of all Asia. Many tried, but all failed. According to legend, even Alexander the Great was unable to untie the Gordian Knot, so he drew his sword and cut it through with a stroke. The expression 'to cut the Gordian knot' is used to refer to a situation in which a difficult problem is solved by a quick and decisive action.