Towards the end of 1944, back with the Rifle Brigade, Trevelyan got a job in the British military mission in Rome, where he remained for two years, falling in love with central Italy.
Later, with the help of German and Italian friends, Trevelyan wrote Rome '44: The Battle for the Eternal City (1981), which provided a vivid account of what it had been like for soldiers and civilians on the other side of the conflict.
[1][3] After the war Trevelyan worked briefly in merchant banking, then became an editor at William Collins, Sons and later at Jonathan Cape and Michael Joseph, editing both fiction and nonfiction while writing his own books.
A 1978 book, A Pre-Raphaelite Circle, viewed the major painters of the early Victorian avant-garde movement of the title through the prism of correspondence he found in the papers of Pauline Trevelyan, a distant relation by marriage who was a confidante and patron of the art critic and artist John Ruskin.
The volume argued for the elevation of his distant ancestor and namesake to the upper reaches of the pantheon of British greats, based on Raleigh's achievements as an explorer, courtier, poet, American colonizer and early purveyor of tobacco to England and potatoes to Ireland.