Catacombs of Commodilla, on the Via Ostiensis, contain one of the earliest images of a bearded Christ. They originally held the relics of Saints Felix and Adauctus. The hypogeum leading to the catacombs was built in the fourth century. The catacombs were used for burials until the sixth century. Later, as happened to other Christian underground cemeteries, it was transformed into a place of worship of martyrdom: restoration of the basilica underground were made by several popes until the ninth century, a sign that the catacombs were still at that time a place of pilgrimage of devout Christians.
There were also found coins bearing the effigy of Pope Gregory IV (827-844) Pope Leo IV (847-855) finally gave the relics of the martyrs Felix and Adautto the wife of Emperor Lothair. Following the catacombs were abandoned and fell into oblivion. It was discovered in 1595 by archaeologist Antonio Bosio, but the first to identify it as that of Commodilla was in the nineteenth century, Giovanni Battista de Rossi. Restoration campaigns were performed at the beginning of the twentieth century and led to the complete excavation of the second level cemetery.
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.