The castle complex on the Willibaldsberg was begun in 1355 and extended in the second half of the 16th century under Martin von Schaumberg. It was transformed into an impressive residence by Elias Holl during the reign of Prince-Bishop Johann Conrad von Gemmingen (1595-1612) – at this stage of the building's history the towers were crowned by onion domes.
Gemmingen also laid out the renowned botanical garden Hortus Eystettensis. Based on the copperplate engravings illustrating the plant collection which were created in 1613 by Basilius Besler, the Bastion Garden opened in 1998 reproduces the plant world of the original botanical garden.
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.