Style which evolved directly from the Roman, suggesting a Byzantine origin, about 500-800 AD. Forged iron, over 2 3/8” length with a tapered shank. Toothed bit folded over forming a narrow lip which would engage a corresponding toothed and slotted bolt end. Rare and can honestly be described as a "castle key” as the length indicates an extremely thick door as would provide fortification protection. Professionally refurbished and stabilized.