"...Arthur was the first born son of King Uther Pendragon and heir to the throne. However these were very troubled times and Merlin, a wise magician, advised that the baby Arthur should be raised in a secret place and that none should know his true identity.
As Merlin feared, when King Uther died there was great conflict over who should be the next king. Merlin used his magic to set a sword in a stone. Written on the sword, in letters of gold, were these words: "Whoso pulleth out this sword of this stone is the rightwise born king of all England." Of course all the contenders for the throne took their turn at trying to draw the sword, but none could succeed. Arthur, quite by chance, withdrew the sword for another to use in a tournament. Following this he became King..."
King Arthur is a legendary British hero,who according to medieval stories,he led the defence of Britan against the Anglo Saxons invaders in the late 5th and early 6th centuries AD. This king has a debated historicity,some specialists say he was real,but others don't, and althought the legend of king Arthur varied widely from text to text,there is no canonical version,they don't have contemporary evidence for him as a historical figure.
This is one of the most popular legends in the world,it has movies too,and even if King Arthur is not real,he will be always be remembered as a hero.
Sources:
http://templars.files.wordpress.com/2007/08/king-arthur-tapestry.jpg
http://www.caerleon.net/history/arthur/page2.htm
https://i.pinimg.com/236x/d5/5f/4c/d55f4cbc28c65c80fa3421673343ecff--swords-rey-arturo.jpg