Over 800 gold and silver coins have been found from the Ann Francis wreckage. Credit: Amgueddfa Cymru / Cardiff University

Archaeologists have finally cracked the code to the famed Ann Francis shipwreck ’s brass combination treasure lock. However, the 16th century relic didn’t open after hours of painstaking trial-and-error. Researchers at Cardiff University and Amgueddfa Cymru, the National Museum of Wales, relied on highly detailed CT scanning equipment to peer inside the mechanical device and learn the code without touching the lock itself.

“It’s not every day you get to solve a 400-year-old mystery,” David Williams , a Cardiff University biomechanics engineer, said in a statement .

The lock’s combination was lost on December 28, 1583, when the merchant ship Ann Francis sailed into a powerful storm during a return voyage from Spain. The exact crew number is unclear, but all of them (around 14 sailors) reportedly drowned after veering off-course and wrecking along the coast of southern Wales.…