MARSHAL, William [1146c-1219] -- Knight-Errant, Lord Marshal
a/k/aPembroke (1199-1219), 1° Earl
William the Marshal
He served four kings — Henry II, Richard the Lionheart, John and Henry III — and rose from obscurity to become a regent of England for the last of the four, and so, one of the most powerful men in Europe.
He has been described as "the greatest knight that ever lived".