Saint-Sever Abbey (abbaye de Saint-Sever) is a Benedictine monastery. It was founded at the end of the 10th century by William II Sánchez of Gascony. According to the monastic chronicles, this was as the result of a vow he made after the battle of Taller, in Gascony, in which he defeated the Vikings (982). In 1060, after a fire, the abbey was reconstructed on the model of Cluny under the direction of the abbot Gregori de Montaner. The Saint-Sever Beatus was the work of monks working under the direction of the same abbot; Abbot Gregori held the post from 1028 to 1072.
The abbey church is a Romanesque building from the 12th century with seven apses. The abbey was listed by France as a historic monument in 1911 and in 1998 it and other sites were jointly designated as the Routes of Santiago de Compostela in France World Heritage site.
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.