La Crête Abbey was a Cistercian monastery in the commune of Bourdons-sur-Rognon. It was founded in 1121 as the second daughter house of Morimond Abbey by Simon de Clefmont, after a failed attempt at a foundation in 1118 at the site now known as La Vieille-Crête. The abbey was very active in founding further monasteries: Les Vaux-en-Ornois in Saint-Joire (1130), Saint-Benoît-en-Woëvre (1132), Les Feuillants (1145) and Matallana in Villalba de los Alcores (1173).
It was suppressed during 1791 in the French Revolution, when the church and conventual buildings were mostly demolished. Little remains of the mediaeval structures, known from a plan of 1705, apart from the chapter house. The gate house of 1715 also survives.
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.