He was the elder son of authors Harold Nicolson and Vita Sackville-West and the brother of writer and politician Nigel.
The boys grew up at Sissinghurst Castle, in the rural depths of Kent, surrounded by the renowned gardens that are now run by the National Trust.
In 1939, he was appointed Deputy Surveyor of the King's Pictures under Kenneth Clark, but soon after, war was declared and he joined the Intelligence Corps, rising to the rank of captain.
Nicolson spent much of his life collecting photographs of early seventeenth-century works in the Caravaggio manner which he wrote about in The Burlington Magazine and which eventually filled three large volumes.
The archive includes material created and collected by Nicolson, largely in a personal rather than professional capacity, throughout his life.