What is the origin of the idiom "king of the hill" and when to use it?

The origin of the idiom "king of the hill" is uncertain, but it is believed to have originated from children's games where the objective is to reach the top of a hill and maintain that position. The person who reaches the top and stays there the longest is considered the "king" of the hill. The expression is used to refer to a person or group who is in a dominant or superior position, often achieved through competition or struggle.