A Gordian knot refers to a problem apparently unsolvable due to its complexity[1], with its origins in ancient Greece.
According to ancient legend, when the kingdom of Phrygia[2] was left without a ruler, the Phrygians turned to an oracle for advice on whom to choose as king. The oracle predicted that they needed to choose the first man they see riding on a cart on the way to the temple of Zeus, which turned out to be a simple farmer named Gordius. Having become the king of Phrygia, he founded a new capital which he named after himself, and in the citadel of the city he installed his cart, giving thanks to the gods for the power he received. Securing the cart to the temple, Gordius entangled the yoke with a complex knot made of dogwood bast. According to legend, it was believed that a person who would be able to untangle this "Gordian knot" would become the ruler of all Asia.
In 334 BC, Phrygia was conquered by the greatest of the generals of antiquity - Alexander II of Macedon. Most of the ancient historians report that as Alexander entered an ancient temple and confronted the cart with its glorified knot, instead of unraveling it he drew his sword and cut it with one blow[3]. However, according to a quotation attributed to Aristobulus, Alexander could have easily released the yoke and the knot by merely pulling the pin which held both[4]. Since then, the phrase "cut the Gordian knot" has referred to a bold, decisive action to a complex problem.