Mühlbacher Klause (Chiusa di Rio Pusteria) castle was built by Sigmund, Duke of Tyrol, between 1458 and the 1480's. It replaced an older fort, built in the 13th century and which was situated about 600 meters west of the present location.
Both fortifications were built here to control the passage through the Pusteria valley which was the border between the counties of Gorizia and Tyrol.
In the 18th century an administration wing, once annexed to the residential building, was destroyed by a flood. Around 1871 the northeastern tower was partly destroyed.
The most recent wartime involvement of the castle dates from the so-called French War at the beginning of the 19th century, when Napoleon's troops were faced by the Tyrolese militia.
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.