Along with the interior view of the Pantheon, this is one of two interior views of a rounded space in the first volume of Le Antichità Romane. Once again, Piranesi accepts the challenge of rendering curvature in two dimensions. Consecrated under Pope Simplicius (468-483 CE), this round church was dedicated to the first-century martyr, Saint Stephen, after his body was believed to have been discovered in the Holy Land. The church is remarkable for its rounded plan; it has no precise equivalent in the Late Antique world (Claridge 308). As such, it is the oldest, centrally-planned church in Rome—a building in which all the parts are organized around the center, symmetrically. 

Piranesi’s view of the interior is captured from the building’s perimeter, looking into its center. The church’s center is a cylinder, surrounded by twenty-two Ionic columns. The cylinder is interrupted in its center by two larger, Corinthian columns, supporting three arches in the center that bisect the church’s center on its diameter. In Piranesi’s view, the tops of these arches are cut off by the upper wall of the ambulatory (the circular passageway around the center); only the spandrels of the arches are present, springing out from the Corinthian capitals. Towards the top of the print, two clerestory windows are seen, framed by the central arch. Such windows continue around the circumference of the cylinder, flooding the interior with light and casting shadows with the columns. The series of clerestory windows acts as a lantern and is the largest light source for the structure. A portico surrounds the center, creating the ambulatory space from which this view is captured. Figures populate the structure and provide a sense of scale, a frequent trope in Piranesi’s prints.  

What the image lacks in annotations, it makes up for in a thorough index entry, in which Piranesi identifies the granite columns as spolia, and remarks on the unequal and varying column widths and ornaments. The index also reveals Piranesi’s visual priorities for the Santo Stefano. It is strictly the building’s interior that appeals to Piranesi, as he concludes his index entry with, “l’aspetto interno di questo Tempio ha un idea della maestà delle fabbriche de’ tempi buoni: lochè mi ha indotto a ritrarne la succennata figura” (Index to the Map of Rome, no. 214). The smaller scale of Santo Stefano would have made its circular interior easier to render than that of the Pantheon, whose monumentality resulted in a somewhat clumsy perspective. (SAH) 

NB: appears to be out of sequence, possibly meant to appear where "Ruin of the Pronaos of the Temple of Jupiter Tonans" appears