With a population of nearly half a million people occupying an area of 8 square kilometers, Naples in 1884 was the largest city in Italy. A great Mediterranean seaport famous for evil smells and foul water, it provided perfect conditions for an epidemic of Asiatic cholera. So well known were the pernicious effects of even a visit to the city that in the final decades of the nineteenth century the Neapolitan economy suffered severely as frightened tourists avoided Naples entirely or made fleeting visits to the ancient sights, where they drank only wine and covered their noses. The press, complained Alderman Vincenzo Pizzuti in 1873, ‘writes of us as if we were semi-barbarian Africans’.

The city faced south onto the Bay of Naples, stretching for three miles in an arc along the coast. To the traveller arriving by sea, Naples rose above the harbour in the shape of an amphitheatre. The Lower City, built on land reclaimed from the Mediterranean, formed the stage. It was enclosed to the north and west by a semicircle of hills; to the east by swamps; and to the south by the waters of the Bay. The stage was divided into two unequal crescents by the spur of the Pizzofalcone hill. To the west stood the small and salubrious neighbourhood of Chiaia; to the east, the teeming slums of the Old City. The slopes of the encircling hills were graced by the elegant homes of the Upper City.

The medical histories of Upper and Lower Naples were sharply divergent, and it was common for local doctors to write of the great metropolis as consisting of two separate cities.