CT Scans Reveal Four-Letter Code to 400-Year-Old Lock from Welsh Shipwreck

Experts from Amgueddfa Cymru and Cardiff University have successfully employed cutting-edge CT scanning technology to unlock a centuries-old combination lock. This remarkable artifact was recovered from one of Wales' most significant maritime discoveries, forming part of the Ann Francis treasure hoard. The brass lock had remained firmly secured since the ship was wrecked off the Welsh coast in 1583. Now, more than 400 years later, researchers have revealed the four-letter code that secured it for centuries: ANCE.

The Ann Francis itself met its fate in a ferocious storm on the evening of December 28, 1583. While returning from Spain, the vessel was blown off course before wrecking on Margam Beach, near Port Talbot. Its extraordinary cargo lay hidden beneath the sand for centuries until metal detectorists uncovered it. The treasure hoard was subsequently acquired by Amgueddfa Cymru—Museum Wales. The majority of the ship's remarkable hoard was discovered by metal detectorist Peter Hughes over a period of 21 years, between 1996 and 2017. Mr. Hughes uncovered the treasure after dredging and storms stripped away layers of sand from Margam Beach, revealing traces of this dazzling 16th-century collection. He recalled his astonishment at the lock's incredible workmanship and astonishing condition, noting, "When I moved the ring dials of the combination they turned with ease after over 400 years beneath the sands and I was left in disbelief."

Working alongside specialists at Cardiff University, museum experts utilized CT scanning technology to meticulously examine the lock's internal mechanism without causing any damage. These scans allowed researchers to identify the correct letter combination and successfully unlock the historic artifact. Dr. David Williams, a research associate based at the Musculoskeletal Biomechanics Research Facility at Cardiff University's School of Engineering, explained the process. "Micro-CT scanning allowed us to look inside the lock without damaging it," Dr. Williams stated. "By creating a detailed 3D image of the internal mechanism, I could see how the notches lined up with the letters and identify the exact combination." He also noted the novelty of the project, remarking, "We normally use this technology to study bones and other biological structures, so investigating a 400-year-old padlock was certainly a first for us." Dr. Williams concluded, "It's not every day you get to solve a 400-year-old mystery."

It is believed the lock once secured a small chest containing items of significant value. Found near a collection of Spanish silver coins and close to two coin weights recovered from the wreck site, the lock may have protected these objects or secured a chest containing valuable items that have not survived, such as documents or textiles. Alastair Willis, senior curator for numismatics and the Welsh economy at Amgueddfa Cymru, highlighted the find's importance: "Elizabethan combination locks are known in Britain, but this one is in exceptionally good condition and is associated with a dated wreck, making it a unique find and the code a tantalizing mystery to solve." Willis added, "Of course, now we've solved it, we are left wondering if the code meant something to its owner." The combination lock is currently among a number of artifacts from the Ann Francis hoard on display at the National Waterfront Museum in Swansea. Other highlights include rare gold coins dating from the reign of Ferdinand and Isabella of Spain, together with a boatswain's whistle recovered from the wreck. The "Tides of Treasure" exhibition is on display at the National Waterfront Museum, Swansea, until September 2027.

What to watch: "Tides of Treasure" exhibition at National Waterfront Museum, Swansea, until September 2027.

Editor's note: Thorough reporting of the CT scan discovery of the four-letter lock code, incorporating quotes, dates, and historical background from the source.