I assume that the person who wrote the title meant King Arthur not Author.  With that cleared up, we all know about he legend of King Arthur and the sword in the stone.  

King Arthur Pendragon was said to be the offspring of King Urther and Queen Igraine.  Queen Igrain was said to have been married to Gorlios who was away at war, because King Urther loved Igrain so much he asked his magician Merlin to transform him into the likeness of Gorlios so that Igrain would love him.  All was going well until the birth of his son Arthur Pendragon.

Because King Urther had become lax in his duties as king he had amassed a number of enemies, Merlin fearing for the boys safety beseeched the King to allow him to have custody of Arthur.  The King finally relented and Merlin place him in the care of a knight Sir Ector, who also had a son of his own called Kay.  Many years passed and Arthur grew up in obscurity, just another son of a knight who became a squire.

After many years had passed King Urther died leaving England divided and warring, seeing this Merlin announced that a test had be produced by God.  Only the true King of England would be able to pull the mythical and magical sword Excalibur from the stone.  Naturally all the men in the Kingdom attempted to pull the sword out of the stone, but to no avail until one young squire who was looking for his adopted brother Kay, and a sword to replace the one he had just misplaced pulled Excalibur out of the stone.

After removing the sword Arthur realised his destiny and was promptly crowned King of England by Merlin.  He quickly dispached all of those that opposed him, and then married Queen Guinevere and formed the knights of the round table.  His best friend and most trusted knight Lancelot was caught having an affair with Guinevere.  King Authur was furious and rather than suffer the wroth of the King Lancelot fled England with Guinevere.  Authur leaving his son and nephew in charge of Camelot followed, it is said that King Authur never returned but he never died, wandering the earth  for his beloved Guinevere and the traitorous Lancelot.  It is said that the one true King (Authur) will return to England in it’s most desperate hour.   

That is an introduction to King Authur, there are other stories told about him and his knights of the round table.