On 24 August AD 79 the long dormant volcano of Vesuvius erupted with sudden and extreme violence. The seventeen-year-old Pliny the Younger, who was staying with his mother and his uncle at Misenum, 40 kilometres westward of the explosion, described the scene in a vivid letter to his friend, the historian Tacitus:

As events turned out, Pliny the Younger’s commendable devotion to his homework saved his life, while Pliny the Elder’s insatiable curiosity – the chief relic of which is his encyclopaedic Naturalis Historia, treating of science, art, natural history and a multitude of allied subjects – proved to be the death of him. Sailing towards the curiously shaped cloud, he soon realised that it was raining a death-dealing mixture of ash and red-hot pumice on to the heavily populated coastline of the Bay of Naples. Trying to save a group of survivors fleeing from the catastrophe, he was overcome by sulphurous fumes and died on the beach near Stabiae.

Even as far from the volcano as Misenum, Pliny the Younger and his mother only just escaped with their lives by taking flight: “Darkness came on… and ashes began to fall… in heavy showers. I derived some poor consolation in my mortal lot from the belief that the whole world was dying with me and I with it. At last the darkness thinned and dispersed like smoke or cloud; then there was genuine daylight, and the sun actually shone out, but yellowish as it is during an eclipse. We were terrified to see everything changed, buried deep in ashes like snowdrifts…”

History does not relate what happened to the unknown young couple depicted in the anonymous Portrait of a Man and His Wife painted on the wall of a house in Pompeii, circa AD 50-79. If they were at home when the volcano blew their chances of survival would have been small. The city was quickly buried under deep layers of volcanic ash and almost its entire population perished in the disaster. Giuseppe Fiorelli, the late nineteenth-century archaeologist who excavated much of Pompeii, made the grisly discovery that in many cases the falling ash and cinders had hardened around whatever it destroyed. This process created an impression which, with the disintegration of organic remains, left a perfect hollow mould and Fiorelli found that by injecting these spaces with plaster he could obtain completely faithful replicas of the bodies of Pompeiians, preserved forever in their death throes. Many of his casts are preserved and the museum at Pompeii even contains one of a dog, its body twisted in an agony felt nearly two thousand years ago.

The Portrait of a Man and His Wife offers a different but equally vivid impression of flesh-and-blood Pompeiians. Its pathos is enhanced by the fact that it is a marriage portrait, showing a couple setting out on their life’s path, full of energy, hope and ambition. Now in the Archaeological Museum at Naples, it was originally found in a house containing several baker’s ovens so it is thought that the couple were involved in baking or patisserie. They saw themselves as rather more than humble tradespeople, to judge by their portrait. The young man, with his large, liquid eyes, is certainly literate because he holds a papyrus scroll under his chin. His wife wears an elegant red tunic and pearl earrings; her hair is coiffed in the style that had become highly fashionable during the second half of the first century AD; and in her hands she holds a stylus and a two-leaved wooden tablet, or diptych, on which to write. She is every inch the type of fashionable young lady so viciously attacked by the Roman satirist Juvenal. Too much make up, he would have said, and too arty for her own good (he hated women with literary aspirations). I rather like the look of her. She looks as if she is about to say something interesting.

If the young man and his wife were involved in baking, I suspect that they were management, not staff. They could clearly afford the services of one of the better portrait painters in town, one schooled in the sophisticated realism of the “Greek style” popular with Roman patrons. The portrait may actually have been painted by an artist of Greek descent, given its remarkable similarity to the only other substantial surviving corpus of first century classical portraits, the “Fayum” heads painted by Greek colonists living in Egypt (of which many brilliant examples are to be found in the British Museum). It certainly disproves the ill-fated Pliny’s observation, in his Naturalis Historia, that “the painting of portraits has died out completely in our time”. It rather reminds me of Ingres, in its combination of extreme artifice – the sinuous but curiously boneless elegance of her fingers, for example – with such close and compelling observation of the human face and form.