The Basilica of Saints John and Paul on the Caelian Hill was built in 398 AD over the home of two Roman soldiers, John and Paul, martyred under the emperor Julian in 362. The church was thus called the Titulus Pammachii and is recorded as such in the acts of the synod held by Pope Symmachus in 499.
The church was damaged during the sack by Alaric I (410) and because of an earthquake (442), restored by Pope Paschal I (824), sacked again by the Normans (1084), and again restored, with the addition of a monastery and a bell tower.
The church has three naves, with pillars joined to the original columns. The altar is built over a bath, which holds the remains of the two martyrs. The apse is frescoed with Christ in Glory (1588) by Cristoforo Roncalli. Below this fresco are three paintings: a Martyrdom of St John, a Martyrdom of St Paul, and the Conversion of Terenziano (1726) by Giovanni Domenico Piastrini, Giacomo Triga, and Pietro Andrea Barbieri.
During excavations performed in the 19th century, a series of Ancient Roman rooms were discovered under the nave of the church. Some of these rooms date back to the first and fourth centuries AD. In one room an elegant third-century AD fresco depicting Proserpine and other divinities among cherubs in a boat can be found, as can traces of another marine fresco and mosaics in the window arches.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.