In the final days of the period of the kings of Athens, there is a legend that King Acastus surrendered his position as king in exchange for the position of archon.
Originally archon was a lifetime appointment, but then a time limit was put on it so that it became eventually an annually-elected position.
Types of Archons
The types of archons were differentiated based on function. There was a polemarch, the archon in charge of war, an eponymous archon, whose name was used for dating events and served as the civic magistrate, and the king or basileus archon for religious affairs. The eponymous archon, not the king archon, was the head magistrate. There were sometimes more than 3 archons.
Etymology: Archon contains in it the root word arche which is found in archaeology and in the Bible, in the first sentence of the Gospel of John, where it is usually translated "beginning," but it also means "rule."