The distant towers in this sketch belong to the Porta San Lorenzo, also known as the Porta Tiburtina owing to its position at the beginning of the Via Tiburtina leading out of Rome. The arch in front is one which commemorates Pope Sixtus V, builder of the sixteenth-century aqueduct, the Aqua Felice. The road is the present-day Via Marsala which runs alongside the tracks of the Termini railway station, on the eastern side of the city whilst the area by the arch is now the Piazzale Sisto V. Another similar view of the road is folio 62 verso (D15414, CLXXXII 61a).
It is likely that Turner conceived of depicting this view because of his knowledge of the drawings of James Hakewill. The sketch is very similar in composition to one by Hakewill, Rome. Looking to the Porta S. Lorenzo 1817 (British School at Rome Library).1 The building on the left-hand side of the road can also be seen in Hakewill’s drawing and has been identified as part of the estate of the de Vecchi family.2