The term “Gordian knot” is commonly used to describe an unsolvable or complex problem.
Tracing back to Alexander the Great, the story depicts the conqueror marching his army into the Phrygian capital of Gordium. Upon arriving in the city, he encountered a wagon with its yoke tied with multiple knots each tightly entangled leaving no answer to how the knots were fastened together.
The wagon belonged to Gordius, the father of King Midas. An oracle had declared that any man who could unravel its complex knots was destined to become ruler of all of Asia.
Alexander became engrossed in attempting to untie the Gordian knot. After struggling with the knot, with no progress or success, he stepped back from the entanglement of ropes and pronounced, “It makes no difference how they are loosed.” He drew his sword and sliced the knot in half with one stroke.