The subject of this sketch is the Church of Santa Costanza, also known as the Mausoleum of Constantina, which stands near the Via Nomentana, north-east of the historic centre of Rome. Turner’s view looks north-east towards the circular drum and cupola of the church, which is dedicated to Constantina, daughter of the Emperor Constantine. On the left are the ruined remains of the elliptical walls of an early basilica built by Constantine, and in the background is the Church of Sant’Agnese fuori le mura which replaced it. Further studies of this complex of buildings can be found on folios 35 and 61 verso (D16454 and D16430; Turner Bequest CXC 40 and 24a), whilst a view of the interior of Santa Costanza appears on folio 62 (D16431; Turner Bequest CXC 25). Like many drawings within this sketchbook, the composition has been executed over a washed grey background.