To arrive at to today's definition, it combined the word "clewe" or
"clew" dating back to the 10th century meaning "a ball of yarn" with the
ancient Greek story of "Theseus and the Matador."
In order to enter the Matador's complex labyrinth, kill the bull-headed monster and solve his way out again, Theseus took with him a ball of yarn and followed it.
By Chaucer's time (Middle English period), the word had taken on the metaphorical meaning of something that leads to a solution. It wouldn't be until later when the spelling became standardized to "clue."
In order to enter the Matador's complex labyrinth, kill the bull-headed monster and solve his way out again, Theseus took with him a ball of yarn and followed it.
By Chaucer's time (Middle English period), the word had taken on the metaphorical meaning of something that leads to a solution. It wouldn't be until later when the spelling became standardized to "clue."