Capriccio of a ruined tower of three bays with, between giant pilasters, a niche with a square panel above raised on a substructure consisting of a series of arches. In the foreground a capital and cornice, and in the distance more ruins and a fortified tower.
There is a highly competent version of this view by Robert Adam in Adam vol.57/127 that shows the decorative detail of this ruin more exactly. The viewpoint for both sketches is the same, although the subject may be a capriccio based on several antique ruins. The niches with square panels above raised on vaulting that can be seen at the Domus Praeconum of the Domus Augustiana may have provided a source (see E. Nash, Pictorial Dictionary of Ancient Rome, London, 1968, vol.I, p.338). It is also possible that the building may be one of the mausolea on the route to Albano, engraved by Piranesi as 'Tempio antico volgarmente detto della Salute su la via d'Albano, cinque miglia lontan da Roma' and published his Vedute di Roma in 1763. It shows a similar use of giant pilaster and panels on top of a basement. The Tomb of Licinianus Piso on the Via Appia provides similar pilaster forms with a niche between. The towered building in the background is the same as that shown in Adam vol.57/111.
In September 1755 Robert Adam and Charles-Louis Clérisseau made a tour to Albano and Ariccia to see 'the remains of the Horatian and Curatian Tombs' (see Adam vol.57/130 and 57/134), and reported returning with a loaded portfolio (see J. Fleming, Robert Adam and His Circle in Edinburgh & Rome, London, 1962, pp.180-1); this sketch and that in Adam vol.57/127 were probably among them.