Gouache on paper.
This is one of thirteen miscellaneous views of Rome by Busiri acquired by Brownlow, 9th Earl of Exeter (1725-1793), whilst on one of two Grand Tours.
Twelve of them, including this one, are inscribed with the location, in the earl’s unmistakeable hand.
Busiri preferred working in the medium of tempera, rather than oil, and many of his finest tempera paintings were acquired by English and Scottish collectors in Rome during the 18th Century.