Opening Ancient Roman Miniature Lock with LWL

Door Ties from Grimbergen · Last updated: October 2026

Archaeologists from the Landschaftsverband Westfalen-Lippe (LWL) discovered a Roman lock made of gold measuring only 1.1 by 1.2 cm. The miniature lock, dating from the 3rd or 4th century AD, was found in Petershagen-Frille and made public in 2025. Using a 3D neutron CT scan, the LWL mapped the mechanism inside.

Such a find shows how old the types of locks we still know today are.

The story behind the Roman miniature lock

Who used the lock, and for what purpose?

The small lock secured valuable items, such as jewelry boxes. According to the LWL, it was made in a provincial Roman area. Dr. Barbara Rüschoff-Parzinger states that this type of lock was used for small objects. Prof. Dr. Michael Rind points out that a gold miniature lock like this is unique in Europe. Moreover, it is the northernmost find of such a lock in Germany.

Source: press release LWL, January 28, 2025.

How does the lock work? CT scan and reconstruction

The CT scan reveals the inner workings

The 3D neutron CT scan shows a sturdy frame with a built-in spring. The bolt and the small key piece are also clearly visible. This allowed the researchers to document the construction without opening the lock.

Scale model of 4:1

Based on the scan, a scale model of 4:1 was made from brass and steel, among other materials. It demonstrates how the frame, spring, and bolt work together to lock the mechanism. The scan also shows damage to the mechanism: someone likely attempted to break the lock open at some point.

CAD file and 3D printed mock-up via TOOOL

For tech enthusiasts, a CAD file is available via TOOOL Netherlands. With it, you can experiment with your own reconstructions. The 3D printed mock-up in purple filament shows how the lock works. Check it out at TOOOL Blackbag.

Why is a gold lock so special?

Roman locks were usually made of iron or bronze. Gold was precious and only used for items of great value. According to the LWL, no comparable gold miniature lock has been found in Europe. The lock was discovered in 2023 and presented in 2025. It says a lot about the craftsmanship of the time and the status of the owner. To learn more about how locksmiths and lockpickers challenged each other throughout the centuries, read about the history of lockpicking.

Source: press release LWL, January 28, 2025.

Get started

Do you have an old lock, for example from a cabinet or chest? With tools for old locks, you can learn how such simple mechanisms work.

Practice only on locks that belong to you or for which you have permission – and never on locks that are in use. Also read whether lockpicking is legal.

Frequently asked questions

How big is the Roman gold lock?

Only 1.1 by 1.2 cm. It dates from the 3rd or 4th century AD.

How does a 3D neutron CT scan work?

Neutrons penetrate through metal. This creates an image of the inside of the lock without having to open it.

Why is the lock made of gold?

Gold was very precious in Roman times. A gold lock indicates an owner of high status and exceptional craftsmanship.

What do we learn from the scale reconstruction?

The model makes visible how the frame, spring, and bolt work together in a very small form.

Next step: History of lockpicking: the unpickable lock