Francis Sheehy-Skeffington was the most unlikely martyr of Easter 1916. The lovable eccentric known as 'Skeffy' to his friends may have been an Irish nationalist, but he also hated violence and regarded the Rising itself as morally wrong.
Whenever someone accused him of being a crank, he would reply: "Yes, I am. A crank is a small instrument that makes revolutions."
Skeffy turned out to be right, but not in the way he had imagined. His murder in cold blood by a half-crazed army officer was a scandal that shocked people on both sides of the Irish Sea.
It was also a key event in turning public opinion against the British authorities who put down the rebellion with such indiscriminate brutality.
Born Francis Skeffington in 1878, the Cavan man specialised in championing unpopular causes. He was a socialist and vegetarian pacifist, who took the highly unusual step of expanding his own surname when he married the suffragette Hanna Sheehy in 1903.
Skeffy scraped a living as a freelance journalist. Hanna was the main breadwinner, but lost her teaching job in 1913 after being imprisoned for breaking windows in Dublin Castle during a protest.
Almost everyone in Dublin knew him, at least by sight. A small man with a bushy red beard, Sheehy-Skeffington dressed in knickerbockers and knee-length socks with a badge reading 'Votes for Women' on his lapel.
His many famous friends included the writer James Joyce, who affectionately nicknamed him 'Hairy Jaysus'.
While Skeffy might have seemed harmless, he took his political beliefs very seriously. When the First World War broke out in 1914, he was sent to jail for making anti-recruitment speeches on the streets.
Although his sentence was six months, he promptly went on hunger-strike and ended up serving just a few days.
Skeffy was on good terms with many of the 1916 Rising's leaders but felt they were making a terrible mistake. On Easter Monday, he tried in vain to save a young British soldier who was bleeding to death outside Dublin Castle.
The following day he went into Dublin city centre, hoping to form a vigilante group that would stop the looting of shops. It was a typically naive idea and he was soon forced to admit defeat.
Disaster struck as Sheehy-Skeffington walked home to Rathmines. He was arrested by British soldiers at Portobello Bridge, apparently for no other reason than that they did not like the look of him.
He then fell into the hands of Captain J.C. Bowen-Colthurst (inset), who had recently been fighting on the Western Front and was probably suffering from shell shock.
In fact, Bowen-Colthurst was even more dangerous than his fellow officers realised. He took Skeffy out as a hostage with his raiding party that evening, during which he shot dead an unarmed 17-year-old boy returning from church.
He also arrested two journalists, even though they were known supporters of the Crown.
Although Skeffy was extremely upset, he still expected to be released soon. Instead, at Portobello Barracks on Wednesday morning, Bowen-Colthurst summoned up a firing squad and had all three of his prisoners executed.
One of the bullets was embedded in a brick which can be seen today as an exhibit at the National Museum of Ireland.
Hanna Sheehy-Skeffington, who had been busy taking food to rebels in the General Post Office, did not find out about her husband's death for over 48 hours. She then had to watch as Bowen-Colthurst's men later tore her home apart in search of incriminating documents.
By then it was beginning to dawn on Bowen-Colthurst's superiors that he was wildly out of control. Anxious to avoid bad publicity, Prime Minister Herbert Henry Asquith invited Hanna to 10 Downing Street and offered £10,000 in return for her silence. She refused and Bowen-Colthurst was eventually brought before a court martial.
He was found guilty but insane, spent 20 months in a psychiatric hospital and then emigrated to Canada, where he died in 1965.
Sheehy-Skeffington's murder was arguably not the worst British atrocity of Easter 1916. Soldiers from the South Staffordshire Regiment were also accused of shooting and bayoneting 15 innocent civilians at North King Street. According to one eye-witness, the killers behaved "like wild animals or things possessed".
It should also be remembered that J.C. Bowen-Colthurst was actually an Irishman himself whose family owned Blarney Castle in Co Cork.
Because Skeffy had been such a popular character, however, his sad story captured the public imagination.
As a symbol of British oppression, it also helped change the Easter Rising's image - from a military fiasco to a moral victory.
The Sheehy-Skeffington name lived on. Their son Owen, just seven years old when the Rising took place, went on to become a lecturer in French at Trinity College and a member of the Seanad.
In 2014, Francis's granddaughter Micheline won a landmark equality case against NUI Galway after the university had denied her a promotion.
Francis Sheehy-Skeffington never expected to be a 1916 martyr - but in 2016 he can also be celebrated as a man who was ahead of his time.