Saint William's Church is a gothic church is known for its sumptuous interior combining the Gothic and Baroque styles. Since the end of the 19th century, the excellent acoustics of the church has allowed it to serve as a venue for concerts of classical music, in particular for the Passions of Johann Sebastian Bach.
Returning unharmed from the Crusades, the knight Henri de Müllenheim undertook the construction of a monastery for the Hermits of Saint William, an order of mendicant monks, in this marshy neighbourhood situated extra muros, that is, beyond the city walls. The elongated building, consecrated in 1301 and realised in 1307, is the only remnant of this group. Entirely brick and unvaulted, the church corresponds well to the ideal of the order, namely by its single nave and the simplicity of its exterior form. Sheltered by a pitched roof, its nave is topped and prolonged by a deep polygonal choir illuminated by high windows, which betrays its original function as the monks' meeting room. In 1331, by reason of its proximity to the port and wharfs, the church was chosen as parish by the newly established corporation of shipbuilders.
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.