The Gordian Knot is a knot that cannot be untied. Today the term is used about a problem that cannot be solved.
The Gordian Knot is a legend about the Phrygians. The Phrygians were without a king and an oracle decreed that the next man to enter the city in an ox-cart should be king. That man was the peasant farmer Gordias.
Gordias’ son Midas, dedicated the ox-cart to the god Sabazios, and the cart was tied to a post with an intricate knot of cornel bark. An oracle declared, that any man who could untie the knots, was destined to rule all of Asia. Alexander tried to untie the knot, but did not succeed. He concluded that it did not matter how the knot was untied, and therefore sliced it in half with hs sword.
Alexander the Great later conquered parts of Asia.