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 since been restored several times. The bell tower is thought to be 14th century.
Well Head (9th century)
The well head in the forecourt is a rare survival from the 9th century. The Latin inscription on the rim reads in translation: 'In the name of the Father and the Son and the Holy Spirit. All who thirst, come to the waters. I, Stephen'. Stephen is thought to have been the sculptor.
Nave
The interior comprises a nave of six bays, which is lined with a variety of ancient columns. There are two aisles.
Apse
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.
The Creation of the Universe
The late-12th century frescoes in the nave are mostly arranged in three registers. The top register depicts Old Testament scenes; the middle register largely depicts scenes of the nativity of Christ; while the bottom register depicts scenes of the Passion and Resurrection.
The cycle starts with the Creation of the Universe. .