More than 40 picture albums detailing the expeditions of the Royal Wiltshire Yeomanry have been moved to a new home in Chippenham.
The collection, now stored in the new multi-million pound Wiltshire and Swindon Record Office, dates back to 1794.
John D'Arcy, principal archivist at Wiltshire County Council, said: "This collection is very comprehensive and has survived astonishingly well.
"The photographs cover most of the military exercises and manoeuvres through the Boer War and all the way to modern day.
"For me, the highlight of the albums is the documentation of the Yeomanry's Second World War campaign in El Alamein.
"The collection is in pristine condition and well worthy of a grand home like this.
"All of the items make fascinating reading and the photographs marvellous viewing - we are very pleased to have them here."
The Royal Wiltshire Yeomanry was formed in 1794 and is the most senior Yeomanry regiment in the Territorial Army.
The albums picture hundreds of men who served with the Yeomanry. They include the late Lord Lansdowne, uncle of the present Lord Lansdowne, who died fighting with the troop in 1942.
The pictures also cover military exercises and manoeuvres on Salisbury Plain in the nineteenth century.
Some of the more unusual items in the collection include menu cards from the First World War, field gun drills and an 1871 handbook on sword exercises.
The collection also includes a personal letter from Brigadier Montgomery praising the Yeomanry for their good heart'.
Several photographs, all clearly labelled with names and dates, include men from Chippenham, Devizes and Calne.
The record centre - and the collection - opens to the public from October 13.
The Royal Wiltshire Yeomanry disbanded in 1967 and formed into two separate squadrons, the Royal Yeomanry and the Royal Wessex Yeomanry.