Although these days we think of Arthur as a fictional king, in the middle ages he was thought of as a real historical figure.
Jean Froissart was one of the most important chroniclers of medieval France. He came to England as historian to Philippa of Hainault, the queen of Edward III (1312 – 1377). In his Chronicles, Froissiart wrote that King Arthur instituted his order of the Knights of the Round Table at Windsor, and assembled there with his knights.
Local legends of King Arthur are perhaps fewer than in the west country but the county of Berkshire does ocassionally appear on the Athurian Map
Ascot is said by some to be the site of Astolat or Shallot, where Elaine and her father Sir Bernard lived.
Eastbury in the Lambourn Valley may well be Esterbury while Rowstock, near Didcot might be where the Lady of Roestoc gave Sir Gawaine a girdle and locket.