San Marcello al Corso was built before 418, when Pope Boniface I was elected there. Pope Adrian I, in the 8th century, built a church on the same place, which is currently under the modern church. On 22 May 1519, a fire destroyed the church. The money collected for its rebuilding was used to bribe the landsknechts, who were pillaging the city during the Sack of Rome (1527).
The work was continued by Antonio da Sangallo the Younger, who rebuilt the church, but a Tiber flood damaged it again in 1530. It was only in 1592–1597 that the church was completed with a facade by Carlo Fontana, commissioned by Monsignor Marcantonio Cataldi Boncompagni. The exterior travertine statues were sculpted by Francesco Cavallini, and the stucco bas-relief over the entrance, with depicts San Filippo Benizio, was created by Antonio Raggi.
Under the main altar, decorated with 12th century opus sectile, are the relics of several saints, which include those of Pope Marcellus as well as Digna and Emerita. The last chapel on the left is dedicated to St Philip Benizi. The late-Baroque decoration contains sculptures by Francesco Cavallini and reliefs by Ercole Ferrata and Antonio Raggi. The first chapel on the left has the double tomb of Cardinal Giovanni Michiel and his grandson Antonio Orso sculpted by Jacopo Sansovino.
The church is administered and owned by the Servite Order since 1369.
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.