The Koppelpoort is a medieval gate in Amersfoort. The gate was built between 1380 and 1425 as part of the second city wall. The whole wall was completed around 1450. The gate was attacked in 1427 during the siege of the city, but this attack was repelled.
The gate was opened and closed every day by the appointed 'wheel-turners'. A minimum of twelve wheel-turners were collected morning and evening by several guards. It was an extremely dangerous task; if they did not begin walking simultaneously, then one could fall, dragging the rest along with often fatal results. Before the gate could come down, it had to be raised, to pull out the iron pins that held it in place. Only then could it come down. While the gate was going down, walking in the wheel grew ever easier and faster, and many people stumbled and broke their limbs. The koppelpoort was also never breached.
The Koppelpoort was given its current appearance during the restoration by Pierre Cuypers in 1885 and 1886. Among other things, Cuypers removed a step between the two gates and replaced it with a slope.
The latest restoration was completed in 1996. It was carried out very cautiously, and with respect for the old building materials.
References:The historical centre of Briançon is a strongly fortified town, built by Vauban to defend the region from Austrians in the 17th century. Its streets are very steep and narrow, though picturesque. Briançon lies at the foot of the descent from the Col de Montgenèvre, giving access to Turin, so a great number of other fortifications have been constructed on the surrounding heights, especially towards the east.
The Savoyards made two raids into French territory in 1691 and 1692. As a result, Vauban was dispatched to inspect the frontier defences, which had been ill-equiped to deal with the attack from Savoy. He returned to the area in 1700 to check on the progress that had been made since his first visit. When Vauban visited Briançon, work on the defences had already started under a local engineer, Monsieur d"Angrogne in 1692.