Going through his papers, I found photographs, documents and articles about a largely ignored, but extraordinary event from the very beginning of the First World War.
I had known the story as a family legend, but here was the first hand proof of what took place.
War was declared at 11.00pm on 4th August, 1914.
The following morning a Royal Naval task force set out from Harwich, lead by the light cruiser
HMS Amphion, following reports of a German ship laying mines in the North sea about 30 miles from shore.
My Great Uncle Robert, as signals officer, was on the bridge with the captain and three other officers when the enemy ship was engaged and sunk.
The surviving German crew were rescued and brought aboard, and the ship turned for home.
At 6.30am on August the 6th, she hit one of the recently deployed mines, the foredeck exploded in a fireball and she began to sink.
Great Uncle Bob was blown into the water, his face and hands badly burned, and survived by swimming under the leaking oil from the dying ship before being picked up by one of the accompanying Destroyers.
Within 15 minutes she was gone, along with 167 men including all but one of the German prisoners.
Great Uncle Bob, along with his brother George, had joined the Navy as boy cadets and risen through the ranks.
Photographs of them reveal tough, muscular men with twinkling eyes and rough hands.
Both had distinguished careers, retired with handsome pensions, a chest full of medals and at least one MBE.
It would take more than a few mines to sink either of them.
The other brother, Melville, was my Grandfather.
He was altogether a gentler, more artistic sort who had survived both TB and a broken heart as a young man, and been left ashore to look after the aged mother.
On hearing of his brother's injuries, he took rooms in Harwich so that he could visit Bob every day at a Naval hospital across the bay.
One evening, whilst waiting for the ferry, he was spotted idly writing a postcard under a gas lamp and promptly arrested as a spy.
Things weren't helped when they went through his pockets and found a sketch of a battleship that he'd dashed off that afternoon.
The guard was called, and he was marched throughout the town by a squad of soldiers,
Jeered and spat at by an angry crowd, he ended up in the cells of the Redoubt, an old Napoleonic fort then serving as the local military headquarters.
In the transcript of his interrogation, the sergeant of the guard asks him for his occupation:
"I make pictures and write stories" he replied...
After an anxious night on an iron bed frame, he was finally released back into a world that had only just begun it's descent into madness and loss.
Largely ignored by history, the sinking of the Amphion appears to involve the very first British, and German casualties of a war that would go on to claim millions.
There are no headstones, no memorials, no visitor centres, just a tiny x on the charts to mark the wreck site.
At 6.30am, on August 6th 2014, at a point on the same latitude as the Amphion's resting place in the North Sea, I marked the moment as best I could.
The sea is a cruel, lonely place that leaves no evidence of past conflicts.
Time means little out here, and a century is just the movement of the waves under passing clouds.
I never met my Great Uncle, but I hope I have honoured him.