1,600-year-old Roman padlock with spring mechanism discovered in Germany — and it's tiny

A metal detectorist in Germany has discovered a 1,600-year-old miniature gold lock that's one of a kind.

An analysis of the tiny lock with CT scans revealed the artifact's inner workings, showcasing its high level of Roman craftsmanship and hinting at trade between northern Germany and Rome in the third century.

"The golden miniature box lock is completely unique in Europe," Michael Rind, director of archaeology for the Westphalia-Lippe Regional Association (LWL), said in a translated statement.

Measuring just under half an inch (1.2 centimeters) in diameter, the tiny lock was identified by metal detector in a field in Westphalia, a region of northwestern Germany, in 2023.

"I could hardly believe it myself when I held the find in my hand," detectorist Constantin Fried said in the statement, "because such Roman locks are usually much larger and are made of iron or bronze parts."

Experts at LWL immediately recognized the gold lock as a miniature version of regular locks made in the Roman provinces in the third and fourth centuries. They would have been used to protect wooden chests similar to today's jewelry boxes, according to the statement.

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All that remains of the miniature lock today is its cylinder, but in antiquity, it would have had a chain and a key, similar to a padlock. In restoring the find, LWL experts found that the core inside the cylinder was made of iron.

To virtually peer inside the lock, the researchers used 3D neutron computed tomography (CT), which uses neutrons instead of X-rays to see inside dense objects like the gold lock mechanism. They discovered that the inner workings of the lock included a spring, guide rail, bolt, baseplate and pin.

The mechanism is largely complete but shows signs of damage. "Someone had obviously poked around in the lock at the time, probably to break it open or remove a blockage," Fried said.

Despite the damage, experts were able to make a large replica of the lock in brass and steel.

This find "shows the high level of craftsmanship of the provincial Roman blacksmith and metalworking trade," LWL Cultural Director Barbara Rüschoff-Parzinger said in the statement, and it has given experts new clues about how elites in Westphalia interacted with Rome during the Roman Empire era.

However, there are no hints as to why this unique, tiny lock was created.

"Was it a one-off or have similar precious miniatures simply not been found before?" Rind said. "We will continue to work on these and other questions."