When he resurfaced he discovered what he had found was not a coin, but a medal belonging to Lance Corporal Stephen Smith of the York and Lancaster Regiment.
Aged 23 in 1915, the young soldier was fighting the Ottoman Empire on the Gallipoli peninsula when he was promoted to Lance Corporal. The next day he was killed.
After polishing up the medal, the divers posted it on Twitter and Lance Corporal Smith’s family got in touch.
Can you help us reunite this WW1 medal with the family of its rightful owner. We found it today in the River Loxley, Sheffield during a search for @syptweet. We believe it belonged to Pte Stephen Smith of the York and Lancaster Regiment. Who was he & does anyone know his family? pic.twitter.com/w4CPAWQZ5A
The family’s instinct was to donate it to the Regimental Museum but there was an issue:
“We needed to know that all members of the family wanted the same thing and that those members of the family were the ones that were entitled to hand it over to us,” said Karl Noble, the Collections Officer at Clifton Park Museum.
“So [we] began a search for tracing the family history and who survived because the man that died had a number of brothers and sisters.
"So there were a number of branches of the family all in different places. We needed to know that we’d asked all of them."
After extensive genealogy work 22 family members were located – with some living as far away as Canada.
One of whom was his great nephew, Reverend Julian Cliff, who said he was surprised to receive a call from the police.
“Anyhow, he [the police officer] said, ‘We think we have discovered some of your family, some of your grandmother’s family’," recalled Reverend Cliff.
“So that was becoming quite a shock to me because I had no idea that my grandmother had any other family than what was known to us and that was very meagre.
“So he said, ‘We’ve discovered that she had five brothers and that this war medal belongs to one of them who the day before had tragically – in one sense –been made up to Lance Corporal and died the next day’.
"Well I really was by this time very shocked, I was emotionally involved in all of this by that time."
It was suggested to Reverend Cliff that all 22 family members should get together at the museum and, more than a century after Lance Corporal Smith’s death, that is exactly what has happened.
“It was quite an event,” said Mr Noble.
“People were there, as I say, who didn’t even know each other existed in some cases, or they’d never met each other and they all introduced themselves to each other. So it was more a joining together of a family, the medal just happened to be the reason.”
As a child Reverend Cliff would wonder why he did not have any cousins and described being introduced to so many relatives as "mind-blowing":
"It literally was emotionally shocking," he said.
He and his wife now plan to visit their Canadian relatives later on in the year.