The Outlaw of Torn

Here is a story that has lain dormant for seven hundred years. At first it was suppressed by one of the Plantagenet kings of England. Later it was forgotten. I happened to dig it up by accident. The accident being the relationship of my wife's cousin to a certain Father Superior in a very ancient monastery in Europe.
He let me pry about among a quantity of mildewed and musty manuscripts and I came across this. It is very interesting—partially since it is a bit of hitherto unrecorded history, but principally from the fact that it records the story of a most remarkable revenge and the adventurous life of its innocent victim—Richard, the lost prince of England.
In the retelling of it, I have left out most of the history. What interested me was the unique character about whom the tale revolves—the visored horseman who—but let us wait until we get to him.
It all happened in the thirteenth century, and while it was happening, it shook England from north to south and from east to west; and reached across the channel and shook France. It started, directly, in the London palace of Henry III, and was the result of a quarrel between the King and his powerful brother-in-law, Simon de Montfort, Earl of Leicester.
Never mind the quarrel, that's history, and you can read all about it at your leisure. But on this June day in the year of our Lord 1243, Henry so forgot himself as to very unjustly accuse De Montfort of treason in the presence of a number of the King's gentlemen.