As Finberg correctly identified, the subject of this sketch is San Paolo fuori le Mura (St Paul ‘extra Muros’, or ‘outside the walls’),1 one of the four great papal basilicas of Rome.2 The church was built on what was believed to be the birthplace of St Paul and is so called owing to its location to the south of Rome beyond the Aurelian walls, the perimeter which marked the boundaries of the ancient city. Turner’s viewpoint here represents the approach from the Porta San Paolo on present-day Via Ostiense, towards the northern façade and the portico of the entrance to the transept. A more detailed study can be found on folio 14 verso (D16511). The early medieval building seen here was almost completely destroyed by fire in July 1823. It was subsequently reconstructed with a similar façade but with a new portico and a different bell-tower. Other sketches of the basilica can be found on folios 7 verso, 10 and 12 verso (D16497, D16502 and D16507) and in the St Peter’s sketchbook (see Tate D16256; Turner Bequest CLXXXVIII 55v).