The church of San Giovanni a Porta Latina may have been founded as early as the reign of Pope Gelasius I (r. 492-96); it was certainly rebuilt in the 8th century by Pope Hadrian I (r. 772-95). The church has been restored several times.
The nave is lined with a variety of ancient columns. It is thought that the frescoes (not in the best condition) date back to the 12th century.
The apse is pierced by three selenite windows, which were added in the twentieth century. The fresco is by Federico Zuccari (1539-1609) and depicts St John the Evangelist.