When I was a boy, my father Michael told me that his grandfather was shot dead during the 1916 Rising as he cycled to work at the Glass Bottle Works in Ringsend on April 29, the day the rebels surrendered.
Not much more was said about the man from Scotland. Not much more was known. There wasn't even a faded photograph to remember him by.
William Gregg's fate didn't seem to count. He died on his way to put in a shift as a bottle blower. His recently discovered death certificate records a sudden brutal death from shock and blood loss caused by gunshot wounds to the stomach.
Like many of the working class Dubliners who made up most of the dead and maimed, William Gregg was no hero.
In 1966 when we celebrated the Rising, only heroes seemed to count.
Back then I remember sitting at an ancient desk in a musty classroom in our old Victorian national school on Thorncastle Street and being mesmerised by the tales of valour and piety displayed by those who fought for Ireland on the streets where we lived.
Michael Malone, the local patriot who fought to the last bullet on Northumberland Road, was the kind of action man that captured our imaginations.
On the morning his unit set up its famous ambush of British troops, Malone was defiant.
"We know what we are dying for. Thank God the day has come," he said.
Not much notice was paid then to the hundreds of Dubliners who were killed for Ireland without volunteering for martyrdom. The luckless illiterate William Gregg didn't get a look in.
But he will now. A century after their violent deaths, the 'collateral damage' of the Rising are sharing the billing with Pearse and Connolly.
An exhibition in April by a group called The Sackville Street Arts Project will honour the forgotten as well as the 'Fenian dead'. It's about time.
I am a television producer. Telling stories is what I do. The mystery of William Gregg's homicide on the streets of Ringsend was a story that had intrigued me for years but that I never investigated.
Apart from a brief entry in the published list of 1916 casualties, William Gregg is a very faint shadow on the page of history.
To find out more I contacted cousins, who contacted other relatives, and we began a collective search for this long lost ghost. We were in for a few surprises.
"Ringsend was the scene of warm work during the rebellion", the Irish Times reported as the corpses were counted and the city smouldered.
"With the best will in the world it was not always possible to distinguish harmless people from the foes of public peace and order. When machine guns came into action the likelihood of being struck by a stray bullet was increased."
We presume William Gregg was one of those unfortunates mowed down in the crossfire. He was 64 years old when he left his home on Simpson's Lane in Irishtown to report for work on that April morning.
He never came back. We don't know where he met his death. Nor do we know who fired the fatal shot.
There were so many dead and dying in that Easter Week of blood and fire, the hospitals were like abattoirs.
At one stage Jervis Street Hospital was treating over 600 citizens for bullet wounds. Imagine that slaughter house for a moment - it's not hard to understand that the details of who died when and how is all a bit hit and miss.
Officially we know that William Gregg's remains were removed to Deansgrange Cemetery for burial with dozens of other casualties.
Last week I went there with my cousin Sean to see if we could locate the grave.
On a bright winter's day we discovered William Gregg resting with his wife Mary McCourt, a Belfast woman, in a publicly-funded restored plot with a new gleaming headstone that bears his name and proclaims simply 'Éiri amach na Casca - civilian casualty of Easter Week'.
None of us knew about the grave or the unsung work Dun Laoghaire Rathdown Council had done to dignify the memory of William Gregg.
It was a poignant moment. But there were more revelations in store.
About 25 metres away we spotted another 1916 headstone. This grave yielded up a remarkable secret.
It was a multiple burial site, containing the remains of a British soldier, three civilians and two insurgents. None were related. One of the rebels was Volunteer Andrew Joseph Byrne.
Andrew Byrne was a labourer from Pembroke Street in Irishtown.
He was not just a near neighbour of William Gregg's, he lived in the same house as my father's parents.
Andrew was a sniper with the 3rd Battalion and served under the command of Eamon de Valera.
He was killed in action in the thick of the gun battles that raged for days, on the railway line near Boland's Mill on Thursday April 27, 1916.
It turns out Andrew was our grandmother Julia's brother.
The epic tragedy of Easter 1916 transformed Ireland. The traumatic deaths of William Gregg and Andrew Byrne took its toll too. Family life would never be the same.
We may never know if Andrew Byrne shared Michael Malone's view that 1916 was a good time to "thank God and die".
We know William Gregg never saw it coming.