Read the short text: "King Arthur is a legendary British leader who, according to medieval histories and romances, led the defense of Britain against Saxon invaders in the late 5th and early 6th centuries. The details of his story are mainly composed of folklore and literary invention, and his historical existence is debated and disputed by modern historians." According to the text, what was King Arthur's primary role in British history?
A) He was a famous writer of romances.