There is an untraceable moment at which the past slips from the realm of memory into deep time. Perhaps it is around the 100-year mark, when those who witnessed any given event have long since died. Just occasionally, technology offers a way down the rabbit hole. There exists, for instance, an 1890 recording of the poet Alfred, Lord Tennyson reciting “The Charge of the Light Brigade”, his response to the account in the Times of that tragic manoeuvre. There are also two recordings, from 1902 and 1904, of the castrato Alessandro Moreschi, a member of the Sistine Chapel Choir for 30 years and one of the last boys to be mutilated for choral fodder.

In this anniversary year of the Battle of Waterloo (18 June 1815), it is worth remembering how relatively new technology preserved an older and more resonant piece of history in the form of a simple photograph of an elderly man sitting on a bench. The man is a venerable but unprepossessing figure; he rests his hands on a cane, he has sabots on his feet, wears cinched gaiters over his trousers and has two medals on his greatcoat.

This is Louis-Victor Baillot, the oldest surviving combatant from Waterloo. Baillot was born in Percey in Burgundy on 7 April 1793, a little over two months after Louis XVI was taken to the guillotine. He died, aged 104, on 3 February 1898, 15 days before the sports car pioneer Enzo Ferrari was born. The photograph was taken a year before Baillot’s death.

As a young man, Baillot was conscripted into Napoleon’s Grande Armée in 1812 and joined the 3rd Battalion of the 105th Line Infantry Demi-Brigade. He travelled to the Vistula in Poland, where his brigade met the remains of the main army as it retreated from the disastrous Russian campaign. He went on to fight at the siege of Hamburg under the implacable Marshal Davout. After a pause in service following the emperor’s exile to Elba, Baillot rejoined the army in 1815 when Napoleon returned to the French mainland and marched with his old brigade to Belgium. On 14 June Baillot saw his commander-in-chief in person for the first and last time when the emperor reviewed his troops before Waterloo.

Four days later Baillot was felled by a sword thrust to the head, delivered by a charging cavalryman of the Scots Greys. He would have died, had not the mess tin he kept under his hat taken the worst of the blow. He was left for dead on the battlefield, where the following day he was picked up and transported to a prison ship off Plymouth as a PoW. In late 1816 Baillot was repatriated and discharged as a consumptive.

Little evidence exists of the remaining eight decades of his life. It is known that he returned to his family home in Auxerre and at some point married a woman named Appoline Charles, with whom he had a daughter and lived quietly at Carisey, in the Yonne. The only things that marked him out as one of Napoleon’s veterans were his fondness for watching the annual parade of the Auxerre garrison, his two medals – the Légion d’Honneur (awarded late, in 1896) and the Saint Helena Medal – and the scar on his head. By the time of his death he was a quietly venerated figure. A decent crowd attended his funeral and watched as his grave was covered with a stone bearing the simple legend “Le Dernier de Waterloo”.

So the old man in the photograph is worth a second look. Those knobbly hands once fired a musket in one of the most celebrated battles in history and those squinting eyes saw Napoleon Bonaparte in his pomp.

Michael Prodger is an assistant editor of the New Statesman