As you may know, Roland (as in the epic Song of Roland) was the warrior-nephew of Charlemagne. Dante placed him in the circle of Mars in Heaven. Like King Arthur, Roland possessed a mystical sword by the name of Durandel.
The blade of the sword Durandel once belonged to Hector of Troy and the hilt contained one tooth of Saint Peter, a vial of blood belonging to Saint Basil, hair from Saint Denis, and a piece of the veil or robe of the Blessed Virgin Mary.
According to tradition, this sword can still be seen today near the Marian shrine of Our Lady of Rocamadour in France. In the photo above, you can see an ancient sword thrust into the rock of Rocamadour. This is the alleged sword of Roland. Thus, this is the true "sword in the stone."
Our Lady of Rocamadour, pray for us.