Trevor Penny was searching for lost and discarded objects in the River Cherwell in Oxfordshire in November 2023 when he made the discovery. The magnet fisher had been down on his luck that day and only pulled scaffolding poles from the water, he told Live Science in a message on Facebook. When Penny lugged out the sword, he didn’t immediately recognize what it was.

“I was on the side of the bridge and shouted to a friend on the other side of the bridge, ‘What is this?’” Penny, who is a member of the Thame Magnet Fishing Facebook group, recalled in the message. “He came running over shouting, ‘It looks like a sword!’”