A brass padlock recovered from a 16th-century shipwreck off the coast of Wales has been opened after researchers used micro-computed tomography to identify its four-letter code. The combination is ANCE, solving a puzzle that finder Peter Hughes had spent years trying to crack.
Hughes discovered the lock in 1999 while using a metal detector on the beach near Margam, in Port Talbot. It was among objects linked to the Ann Francis, which was caught in a storm on December 28, 1583, while returning from Spain. The ship’s cargo remained buried beneath the sand for centuries.
Researchers from the Amgueddfa Cymru museum and Cardiff University scanned the lock to examine its internal mechanism. Cardiff University engineering researcher David Williams said the equipment was not designed for this task. After an initial scan showed that the letters could be seen, a different approach on the third scan revealed the code.
The lock has four rotating rings, each with six letters, giving 1,296 possible combinations. Chief curator Alastair Willis said the letters also had to be aligned with the loop at the top, while other fixed letters on the ends were unrelated to the code.
The lock was found close to Spanish silver coins and two weights used to measure coins. Curators believe it may have secured these objects or a small chest containing valuables such as documents or textiles, which have not survived. The lock remains in working condition, but what it once held is unknown.
Hughes donated his collection of historical finds to Amgueddfa Cymru in 2017. The objects, including the padlock, were displayed at Swansea Waterfront Museum in July 2026.
Sources: Folha Ciência.