Saint Gertrude's was an Augustine abbey, limited to 12 canons of noble descent. The church was built from the 14th to the 16th century. The tower has an openwork spire, dating from 1453. Inside is an 18th century carillon.
The abbey was closed in 1796 (during French occupation) and the buildings got other uses. In 1919 it became a Benedictine abbey. Reconstructions were carried out after the fire during World War II. The abbey grounds (compound outside the church) at present has mixed uses, and is like a little pleasant park to hang out or have a quiet rest.
During the second world war, the church (as many others in Leuven) was seriously damaged. The artistic choir stalls seemed beyond repair. Fortunately photographs existed. After the war, the stalls were recreated by sculptors, who did an excellent job. The choir with its many wooden sculptures is now one of Leuven's most outstanding works of art. One can distinguish between original parts and later parts by judging the colors of the wood, the older parts being darker.
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.