Fought (perhaps) around the year 500 A.D. - this was a battle between The Britons and a large (unknown commanded Anglo-Saxon raiding party/army). Many parts of the battle are considered speculation and the stuff of legend. This is to include the fact that King Arthur led the Britons! As the "legend" goes, around 960 Anglo-Saxons warriors attacked Briton positions at Mont Badon. Arthur (at the front of his army), led the charge holding "The Cross" before him. The "Cross" may have been a shield painting (but some versions have him holding a Cross before his enemy).
Perhaps "The Cross" as a pseudonym for his famed equally "legendary" sword - Excalibur! It was said in the legend that he lost some 970 to 980 men, but won the battle after the enemy lost suffered similar losses and retreated. Although the proof of a real Arthur will no doubt remain "historical legend", there IS archaeological proof that a battle was found in the area (and around the same reported time). Another "Battle of Badon" was fought around the mid-630s A.D.