This key from the fifteenth century is made of iron and is about 118 mm long. It has a kidney-shaped bow (the part at the top of the key) and a simple bit (the part inserted into the lock), forming a right angle with the shank. Its iron material distinguishes it from other keys made of copper alloys, though iron is more common. It belongs to a group of keys that are roughly this length while a shorter group is closer to 30 mm. Its length and shape help to classify it as a door key.
The key’s group is called 7A (or G1), which refers primarily to the shape of its bit. Casket keys are smaller (around 30 mm), while padlock keys are sometimes longer and have a smaller bit (fig. 2). The kidney-shaped bow helps date this key to the fifteenth century, with circular and heart-shaped bows more common in the thirteenth and sixteenth centuries respectively.