The sketch on this partial, torn page represents part of a view of the Bay of Pozzuoli, approximately eight miles west of Naples. The composition continues on the opposite sheet of the double-page spread, see folio 91 (D15735; Turner Bequest CLXXXIV 89), but the details on this side include the distant island on Nisida visible on the horizon. The line of blocks projecting from the sea meanwhile represents the remains of the Roman breakwater of Pozzuoli, popularly known as the Bridge of Caligula. According to legend, Caligula constructed a floating pontoon of boats in order to disprove a prediction that he would no more become Emperor than ride across the Gulf of Baiae with horses. The bridge was three miles long and stretched between Pozzuoli (ancient Puteoli) and Baia. This story formed the subject of a later oil painting by Turner, Caligula’s Palace and Bridge exhibited 1831 (Tate, N00512).1 During the early twentieth century the surviving piers of the Roman structure were incorporated into the modern sea wall which stands today.
Martin Butlin and Evelyn Joll, The Paintings of J.M.W. Turner, revised ed., New Haven and London 1984, no.337.