The diaries of a naval wife who tended Lord Nelson's battle wounds at sea have been rediscovered by a historian from Lower Godney.

A chance find of a battered paperback on a stall at Priddy Folk Festival has resulted in Senior Lecturer in History at Bath Spa University Dr Elaine Chalus winning a major research grant to investigate diaries kept by Elizabeth Wynne, who married one of Nelson's famous "band of brothers" – Captain (later Admiral Sir) Thomas Francis Fremantle – during the Napoleonic Wars.

"I read it and its an amazing story – it is just extracts from the 30 volumes of the diaries. It took a while to find the rest of the volumes, but they turned out to be in the family archives on the estate in Buckinghamshire she bought with her dowry and which remains in the family," said Dr Chalus.

Dr Chalus will use her funding award of more than £100,000 from the British Academy national body for the humanities and social sciences to bring to light the 40 volumes of diaries, most of which have never been published, and to write a biography of Elizabeth and her descendents.

The story of Elizabeth Wynne could come straight from the pages of a Jane Austen novel.

Elizabeth, known as Betsey, began the first volume aged 11 in 1789, only weeks after the outbreak of the French Revolution, and kept up her journal until she died in 1857. The diaries tell of a remarkable life shaped by revolution.

This included years with one of Louis XVI's leading political agents and his family in Switzerland, evacuation by the British Navy from Livorno and her marriage to Fremantle in 1797, organised by Nelson's mistress Emma Hamilton.

Betsey then sailed into war with Fremantle on board his ship in Nelson's fleet. When Nelson lost his arm in a battle off Tenerife he was evacuated on Fremantle's ship, the Seahorse, where Betsey was sailing with her husband she was on board nursed him on the voyage home. Fremantle later fought alongside him, and survived, at Trafalgar.

Dr Chalus hopes not only to revive interest in a little-known diarist but to look at the bigger historical picture in the 18th and 19th centuries via the eyewitness account of a woman who participated in key events at a time of important social, cultural and polit ical transition.

During her research Dr Chalus will also study other prominent members of the Fremantle (later Barons Cottesloe) family. It was Betsey's son Charles, for instance, who laid claim to Western Australia for the Crown. A small number of Betsey's diaries were published in the 1930s, but the vast majority of her 40 volumes have remained unknown. They are still in the family's possession in Buckinghamshire, where Dr Chalus tracked them down.

Dr Chalus said: "All this started for me when I chanced upon a battered paperback copy of extracts from the diaries on a book stall at the Priddy Folk Festival.

"The Cottesloe (Fremantle) family trust is enthusiastic about my project and has been kind enough to give me unrestricted access to the journals and an extensive private family archive.

"One of the amazing things is the way the diaries mirror the fictional stories of Sharpe or Flashman – the Fremantles seem to have turned up everywhere.

"What her diaries show is how cosmopolitan life was for people like Betsey."

Dr Chalus will write a generational history of the Fremantle/Cottesloe family, described as an "intimate history of Empire" as well as a popular history of the family.

In her initial research Dr Chalus has already taken more than 4,000 digital images of Betsey's journals. After 200 years she now hopes to give the admiral's wife her rightful place in history.