Gordian Knot

The Gordian Knot is a legend of Phrygian Gordium associated with Alexander the Great. It is often used as a metaphor for an intractable problem (disentangling an "impossible" knot) solved easily by loophole or "thinking outside the box" ("cutting the Gordian knot"):

Turn him to any cause of policy,
The Gordian Knot of it he will unloose,
Familiar as his garter

At one time the Phrygians were without a king. An oracle at Telmissus (the ancient capital of Phrygia) decreed that the next man to enter the city driving an ox-cart should become their king. A peasant farmer named Gordias drove into town on an ox-cart. His position had also been predicted earlier by an eagle landing on his cart, a sign to him from the gods, and, on entering the city, Gordias was declared king. Out of gratitude, his son Midas dedicated the ox-cart to the Phrygian god Sabazios (whom the Greeks identified with Zeus) and tied it to a post with an intricate knot of cornel (Cornus mas) bark. The ox-cart still stood in the palace of the former kings of Phrygia at Gordium in the fourth century BCE when Alexander arrived, at which point Phrygia had been reduced to a satrapy, or province, of the Persian Empire.

Several themes of myth converged on the chariot, as Robin Lane Fox remarks: Midas was connected in legend with Alexander's native Macedonia, where the lowland "Gardens of Midas" still bore his name, and the Phrygian tribes were rightly remembered as having once dwelt in Macedonia. So, in 333 BCE, while wintering at Gordium, Alexander the Great attempted to untie the knot. When he could not find the end to the knot to unbind it, he sliced it in half with a stroke of his sword, producing the required ends (the so-called "Alexandrian solution"). However, another solution is presented by Aristobulus, which indicates "he unfastened it quite easily by removing the pin which secured the yoke to the pole of the chariot, then pulling out the yoke itself." That night there was a violent thunderstorm. Alexander's prophet Aristander took this as a sign that Zeus was pleased and would grant Alexander many victories. Once Alexander had sliced the knot with a sword-stroke, his biographers claimed in retrospect that an oracle further prophesied that the one to untie the knot would become the king of Asia.

...
Wikipedia