Alma Place in Oxford and Inkerman Close in Abingdon commemorate two of the bloodiest battles of the Crimean War of 1854-56 - just two examples of how that war still resonates, if faintly, today. We remember Florence Nightingale, and perhaps a line or two from Tennyson's Charge of the Light Brigade ("Someone had blunder'd"). Balaclava helmets, once protection against the cruel Russian winter, are now the disguise of terrorists everywhere.

Few people recall exactly why the British, French, and Turkish forces engaged so ruthlessly with the Russian army of Tsar Nicholas I, or realise how significant the campaign was in the history of modern warfare. Mines and exploding shells were used, and for the first time the grim realities of life at the front were conveyed to those at home through photographs and rapid news reports, conveyed by telegraph.

In Mrs Duberly's War, Oxford-based historian Christine Kelly has rescued a fascinating contemporary eye-witness account of the conflict from semi-oblivion, and put it into context for today's readers. The book is based on the journal and letters of Frances Isabella Duberly, wife of Henry Duberly, regimental paymaster of the 8th Royal Irish Hussars.

Through determination and charm, Fanny Duberly (1829-1903) managed to spend the entire war with her husband, despite the disapproval of the authorities. She lived partly on board ship in the Black Sea and partly camping in a 9ft 8in square tent, braving freezing weather, inadequate rations, and appallingly insanitary conditions, alongside the soldiers.

It was a dangerous life, but also an exciting one for a Victorian woman who would have enjoyed little freedom at home. An accomplished horsewoman, Mrs Duberly rode around the beautiful and unfamiliar landscape "as free as the winds of heaven"; came under fire more than once; witnessed the Battle of Balaklava; and rode through the ruins of Sebastopol. She shocked many by wearing trousers under her skirt, was criticised for her alleged flirtatiousness and for intruding into a man's world', and cruelly parodied in Punch.

But she should be acknowledged as one of the first female war correspondents. "Today she would be a Kate Adie or Orla Guerlin." said Christine. "She had courage and curiosity, and a real way with words. In her description of the Light Brigade coming back she conveys so well the shock of this immaculate regiment just disappearing." She evokes the chaos of war, as in this description of Balaklava harbour: "Ships were crushing and crowding together, all adrift, all breaking and grinding each other to pieces."

Christine has interwoven Fanny's journal - written with publication in mind, and published in 1855 - and excerpts from her personal, previously unpublished, letters to her sister and brother-in-law. The journal is formal and Victorian in style and it is clear that she has censored herself or been censored by her original editor (her brother-in-law).

The letters, often about the same subjects, are very different: "more outspoken, funnier, angrier, and less beset with purple passages", said Christine. Some of them read like modern emails, with abbreviations and a breathless indifference to punctuation. We feel Fanny's visceral horror at the death and destruction and her disgust at the incompetence and "accursed mismanagement" of the British command, as well as learning about her crush on the Turkish forces' commander Omar Pasha, and the minutiae of her domestic life, as she tries to keep up the semblance of gentility in unpropitious circumstances.

Christine's interest in the Crimea was sparked off by a family connection. Her great grandfather's older brother, John Warren, was a combatant and later died from cholera and his wounds. She transcribed all the letters he wrote from the front: "I thought they were extraordinary; so modern, and so evocative of what was going on."

Officers and men wrote more than a million letters from the Crimea, and these were not censored. Some were printed in the British press and had a significant influence on public opinion, leading to better management of the war effort and humanitarian intervention to improve living conditions and medical care.

Ms Kelly initially wanted to produce a book of these letters, but her publisher suggested editing Mrs Duberly's journal. When she began reading the letters, in the British Library, she was convinced that this was indeed a woman she wanted to live alongside. "What I enjoyed was uncovering what she was really like, and allowing her to speak for herself, because she has become such a myth. Now I have the satisfaction of feeling that she was worth bringing back to life."

Mrs Duberly's War is published by Oxford University Press at £16.99.