X-Ray Scans Crack Four-Letter Code on 1583 Shipwreck Padlock

A brass combination padlock from an Elizabethan shipwreck has been opened for the first time in more than 400 years. According to Live Science, researchers at Cardiff University in Wales used micro-CT scans to work out its four-letter code, "ANCE," without damaging the mechanism.

The lock belongs to the Ann Francis treasure hoard, named after a British merchant ship that was wrecked in a storm off Wales in 1583. Now that the code is solved, a new question remains: why that word was chosen.

What is the Ann Francis padlock?

It is a brass combination lock that researchers believe once secured a chest aboard the Ann Francis. At some point it became separated from whatever the chest held. Amgueddfa Cymru — National Museum Wales acquired the lock, which was found among the ship's lost goods on Margam beach in South Wales.

Metal detectorist Peter Hughes found the lock and much of the hoard, including gold and silver coins, between 1996 and 2017. Live Science reported that dredging and storms in recent decades have exposed parts of the ship's lost treasure on the beach. Hughes found the lock near a previously unknown stash of Spanish silver coins and coin weights.

How did researchers open it?

The team used micro-CT scanning, which takes thousands of X-ray images and assembles them into a 3D digital model. By matching notches inside the lock to the letters on the outside of the model, they identified the correct four-letter combination.

Hughes said he had tried for many years to open the lock himself without finding the code. After the museum acquired it, staff worried because they could hear grit moving inside the dials. With more than 1,000 possible combinations, they did not want to risk damaging it by trying them one by one. The scan offered a way to look inside without harm.

David Williams, a research associate at Cardiff University's Musculoskeletal Biomechanics Research Facility, said in a statement that the team normally uses the technology to study bones and other biological structures. He called the padlock a first for them.

What happened to the Ann Francis?

According to Amgueddfa Cymru, the ship was owned by Francis Shaxton, a merchant and known smuggler. He claimed the vessel was sailing along England's eastern coast from King's Lynn to Hartlepool. In fact, the museum says, it was heading the opposite way, to Spain with a cargo of wheat. Spain depended on grain shipments at the time and paid for them in gold and silver from colonial conquests in Central and South America.

On the return voyage, a violent storm hit the ship on the evening of Dec. 28, 1583. It was driven off course and wrecked off Margam beach.

A parish register recorded the loss of 14 sailors that month, who may have been the ship's crew, the museum says. Their deaths were blamed on a supposed witch. Locals quickly looted the wreck, and a legal dispute followed over who had rights to its goods. One Welsh lord who claimed the wreck listed the items he impounded, including cannons, guns, part of a mast, Spanish silver and three chests with broken locks. According to the museum, the newly opened lock could once have secured one of those chests.

Why does it matter?

For museums and researchers, the case shows that a medical-style imaging tool can reveal how fragile historical objects work without damaging them. The lock itself is unusual. Alastair Willis, senior curator for numismatics and the Welsh economy at Amgueddfa Cymru, said in the statement that Elizabethan combination locks are known in Britain. This one, however, is in exceptionally good condition and is tied to a dated wreck, which he said makes it a unique find.

Hughes said the dials still turned easily after more than 400 years beneath the sands, and that he was "left in disbelief."

What is still unknown?

The code, ANCE, is the open question. Willis said the team is now wondering whether the code meant something to the lock's owner. The sources do not suggest an answer, and no explanation has been offered for why those four letters were chosen.

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Around Prague, based on reporting by Live Science