Barbarossa’s son Heinrich VI had the Richard I, the king of England, kidnapped on his return from the Third Crusade and incarcerated in the imperial Reich castle at Trifels, in an act of vengeance for Richard`s alleged murder of one of Heinrich`s relatives.
Richard was held prisoner until a ransom of some 150,000 Marks was paid, prolonging the rule of his unpopular brother King John and the exploits of his legendary adversary Robin of Loxley/ Huntington or wherever he may have hailed from.