The manuscript with the title Daring All things – My Story was the unpublished autobiography of British Army chaplain George Kendall OBE (pictured) and gives a first-hand account of the capture of the rebel leaders.
Kendall, my grandfather, was chaplain to the 59th division of the British Army who were sent to Dublin to help put down the Rising. He describes in his memoir, completed in 1961, shortly before his death, the capture and execution of rebel leader James Connolly.
"I saw James Connolly twice whilst he was in hospital, the second time being on the eve of his execution.
"Speaking to me on the first visit, he said in answer to a question of mine about his attitude – 'You must know the saying.' 'What saying?' I asked. And he replied: 'The price of liberty is eternal vigilance.' This too was the saying I heard as I spoke to his men in the Dublin Castle hospital.
"Listening, I felt it was not my duty to condemn, or argue. Connolly was, for years, a professed agnostic, but at the hour of death, he returned to the faith of his fathers. That night a Catholic priest was admitted to the hospital and he administered Holy Communion to Connolly and gave him absolution.
"Asked to pray, at the end, for the soldiers about to shoot him, he said: 'I will say a prayer for all brave men who do their duty.'
"And so he died, the last of the Sinn Feiners to be executed," he wrote in his memoir.
Born in a small Yorkshire village, George Kendall became a Primitive Methodist Minister. In 1913, while canvassing for new members for his church outside Windsor Castle, he was invited to tea by Queen Mary and became a lifelong friend of the British royal.
He was among the reinforcements rushed to Dublin in the aftermath of the 1916 Rebellion on Easter Sunday.
"Personally, I was fond of the Irish people and therefore overwhelmed by this tragedy caused by the misguidance of the leaders of the rebellion," he wrote in his memoir, never before seen until I uncovered the book.
"But there was another cause. Many loyal and committed men told me it was their considered opinion that the outbreak would have been impossible but for the gross and unpardonable laxity, long continued, of the Irish government at that time."
He then goes on to describe the drama of the unfolding Rising and eventually the capture of its leaders.
"The Mad Rising, as it was called by the Irish people, was a black one not only for Dublin and Ireland but for the whole of our empire of those days and our allies ... I stood in the middle of blazing streets with snipers' bullets whizzing around ... I entered Liberty Hall when it was captured ... I visited Dublin Castle and talked to our wounded and the Sinn Feiners. They were lying in the same wards and receiving the same treatment."
After witnessing the capture of Markievicz "in her brilliant green male uniform", he was given her fur rug – and kept it for years "until it perished of moth".
Kendall also briefed the British prime minister Herbert Henry Asquith when he came to Dublin in the aftermath of the Rising.
Although he put some of his experiences in the memoir, including a brief chapter on Dublin in the aftermath of the Rising, he said, "half my story will remain untold" because of the confidential nature of his .
The family have never known about the book even though my parents honeymooned in Ireland and, in 1994, I flew all over the country by helicopter to photograph it for my own book, Ireland from the Air.
Now I am hoping to have my grandfather's book published and his story of the First World War will be featured in a British television special later in the year.