This atmospheric study was probably made during Leighton's visit to Spain in the late summer or early autumn of 1866. As the Ormonds observe, 'the country had a profound attraction for him, and he later became something of a pioneer in the study of Spanish art, devoting one of his discourses to the subject' (op.cit; p. 95). A number of other landscape sketches painted in Spain are recorded, including one in the Tate Gallery (Ormond, no. 516, pl. 134; exh. Leighton, Royal Academy, 1996, no. 36, repr. in cat.) and one at Leighton House (Ormond, no. 517). There is also a sketchbook in the Royal Academy (LEI/26) which dates from the 1866 visit and contains views of Toledo, Seville, Cordova and other Spanish cities (see lots 49-51).
Leighton made many landscape sketches on his extensive travels, invariably on a small scale and usually rectangular in format. The present example is typical in this respect, but in no other. Very few of his landscapes contain figures, and this one seems to be unique in being painted at night. We can imagine him doing it after dinner from a hotel bedroom or balcony, suddenly moved by the abstract forms of the harbour by moonlight. The effect is reminiscent of Whistler, or even some exponent of British impressionism a generation younger. The comparision, however, shows how innovative Leighton was, since Whistler did not paint his 'nocturnes' until the 1870s, and the New English Art Club, the chief forum for British impressionism, was not to be founded for another twenty years.