Knight and vassal
A knight is leaving his castle with his little army of men for the war. He turns to the vassal nominated to keep the castle safe : "In addition to my castle, you will keep my wife's honour, this is the key to her chastity belt, I trust you, now I should leave to fight for the king!" Ten minutes later, as the troop ride in silence, they hear a noise from behind. They halt and see the vassal running with the key in his hand. As he reaches the knight, he says, out of breath: "Sir, sir, it's not the right one!"