William the Marshal is reported to have been the greatest Knight in all history.
He served many Kings, but he first served Henry Plantagenet; Count of Anjou, Count of Maine, Duke of Normandy, Duke of Aquitaine, Count of Nantes, King of England and Lord of Ireland. Henry II proved one of the greatest, long lasting and most powerful rules of the medieval period. William the Marshal served Henry as the master of his guard and soldiery. He would go on to serve Richard the Lionheart, John and Henry III.
But before that he faced down Richard while that King's son was rebelling against his father.
In Henry's final year, in the last few months of his long reign he faced Richard and Philip the King of France. The two allies tore through Henry's domains like a whirl wind, largely because Henry stood upon death's door and his barons knew it and refused to fight the French and the soon to be King of England. But even after most of all deserted the old King William did not.
During the battle for Le Mans Henry's dwindling army was bested and forced to withdraw. William covered the retreat and ran straight into Richard's advance horse. Richard was with them and they had the worse of it, so much so that the Lionheart shouted to William "By God Marshal, do not kill me. It would not be a good deed as I am unarmed!"
To that William responded "I'll not kill you Prince, I'll let the devil do that!" He lanced his horse and made good his escape.