The Remnants of an Army, exhibited at the Royal Academy in London in 1879, commemorates the outcome in 1842 of the first British invasion of Afghanistan. The exhausted man on horseback is army surgeon Dr William Brydon, the first of the few survivors who collapsed back from Kabul to Jalalabad after a disastrous campaign.

Remnants was painted by Elizabeth Butler, the foremost war artist of the mid-Victorian age. Butler rarely painted actual combat, concentrating instead on the more muted aspects of war, portraying the fear, stoicism and suffering of soldiers. "My own reading of war," she wrote, "that mysteriously inevitable occurrence throughout the sorrowful history of the world - is that it calls forth the noblest and basest impulses of human nature."

She was born in 1846, the elder of two sisters, to Thomas and Christiana Thompson, a well-to-do English couple. As a child she was educated by her father, whose interest in contemporary history translated itself into colourful tales of derring-do for his two daughters. It was from him that Elizabeth learnt of the 5,000 troops and 15,000 civilians who died in the British retreat from Kabul in 1842.

She grew up socially timid, but with a strong sense of her own self-worth. Her choice of career, painting, was not unusual for artistic young women of her class, but her choice of subject matter was. Military subjects were seen as the preserve of male artists.

Two years before painting Remnants, Elizabeth Thompson had married a soldier, Major William Butler from the Suir Valley, near Golden, Co Tipperary. Her husband, a man of forceful liberal views, stirred her interest in the politics behind the British military engagements and in "the Great Game", the name given to the rivalry between Britain and Russia for the control of Central Asia.

Afghanistan was an important piece in this game. It was an independent kingdom of the north-west frontier of British India, and for Britain it was a critical buffer between India and the expanding Russian empire to the north.

The ruler of Afghanistan, Sher Ali, tenacious of his country's independence, accepted subsidies from the two great powers, playing one off against the other, and this situation led to a crisis in 1878, when a Russian diplomatic mission was allowed into Kabul while a British diplomatic mission, sent to counteract Russian influence, was stopped at the Indian frontier.

The response of the Viceroy in India, Edward Lytton, was to launch the second British invasion of Afghanistan. This invasion led, after some three years, to a satisfactory outcome for Britain, which secured its own man on the Afghan throne. But before this was achieved, some serious military and diplomatic reverses were to be suffered.

At the start of the 1878 invasion, opinion in Britain was polarised. Both the Butlers opposed the invasion. William Butler contributed to the impassioned debate with a magazine article strongly arguing against British involvement in Afghanistan. Elizabeth Butler's response to the invasion was to paint The Remnants of an Army. The painting was popularly hailed as the picture of the year in 1879. Viewers cried before it, deeply affected by its graphic presentation of suffering and stoicism.

The incident portrayed, Brydon's arrival at Jalalabad in 1842, was not a contemporary one. It was ostensibly a historical subject, so the painting's subversive quality was missed and Butler's oblique criticism of imperial policy was not seen.

It would be more than a decade later, with her most famous Irish painting, Evicted, a powerful iconic study of the aftermath of a Wicklow eviction, that she would make her most overt statement about state power and its uses. The painting now hangs in the Folklore Department of UCD.

Butler's paintings were unfashionable by the end of the 19th century, when jingoistic imperialism was at its height. But throughout her long life, she continued to draw on military subjects for her work. The sombre In the Retreat from Mons was painted and exhibited in London as late as 1920.

She died at Gormanston Castle in 1932, and is buried in the local cemetery at Stamullen.

Martin Ryan's biography of William Butler will be published next year