Stelling van Amsterdam

was involved in all defence lines around Amsterdam since 1787, in particular the Posts of Krayenhoff named after him. A combination of inundation and posts to protect Amsterdam date back as far as 1629, when these were prepared against a planned but later cancelled attack from the south by the Spanish general Ernesto Montecuccoli during the Eighty Years' War. Another water defence line was prepared in the south in 1672, the Rampjaar, but the invaders failed to get past the Old Dutch Waterline. In June 1787, 27 posts were created by the Patriots and on 18 September 1787, the surrounding polders were inundated. These posts held back the Prussian invasion, but the Prussians managed to get access through the Haarlemmermeer and successfully attacked the posts from behind. When the English invaded Holland in 1799, a water defence line was created north of Amsterdam, led by engineer Cornelis Krayenhoff. In 1800, the was created led by Krayenhoff to the west of Amsterdam, fearing another invasion by England. When the threat had decreased the next year, the posts were neglected. In 1805, Krayenhoff was tasked with creating a new defence line, because King Louis Bonaparte feared annexation by the First French Empire. The posts would be built in 1809 and 1810 at a distance of 8-12 km from the city, and would become known as the Posts of Krayenhoff. The Incorporation of the Netherlands in 1810 was peaceful, so the posts were not used. Plans were made to improve the posts, but they were never executed because of the liberation of the Netherlands in 1813. In the following decades, new forts would be added to the Posts of Krayenhoff in the poldered Haarlemmermeer: Fort near Heemstede, Fort along Schiphol, Fort along the Liede, Fort along the Nieuwe Meer. ==Function==

The was primarily a defensive water line (). In the event of an enemy attack, large tracts of land around Amsterdam would be inundated with water, preventing the enemy from advancing. Amsterdam would function as a national redoubt or reduit, as the last stronghold of the Netherlands. Forts were built in which roads, railways or dikes crossed through the water line. At such locations, there would be no water to stop the enemy and so the forts were intended to shell the enemy. ==Construction==

The law for the construction of the was passed in 1874, a few years after the Unification of Germany, which placed a powerful new great power on the eastern border of the Netherlands. During the planning prior to its construction, the design was already obviously outdated by modern technical advances. The invention of the high-explosive shell and the percussion fuze, which allowed ordnance to explode on impact and dislodge brick fortifications easily, necessitated a change from masonry to concrete forts. The Dutch did not have the required experience yet using and building with concrete and so extensive tests had to be performed. Concrete structures were shelled with the heaviest artillery available at that time. Further delays resulted from the fact that the sand foundations had to settle for several years before the forts could be built on them. Only in 1897 could the actual construction finally begin. ==Service==

The Stelling van Amsterdam has never seen combat service and the use of aircraft rendered it obsolete after World War I. It was, however, maintained and kept in service until it was decommissioned in 1963. The dike through the Haarlemmermeer, which made it possible to inundate the southern portion of the polder while the northern portion could continue to produce food for Amsterdam, is now cut by the A4 motorway. The motorway also goes under the Ringvaart at Roelofarendsveen, which makes the inundation of the Haarlemmermeer Polder and thus the future use of the Stelling no longer possible. In 1996, the complete Stelling was designated as a UNESCO World Heritage Site, which was extended in 2021 with the New Dutch Waterline to form the Dutch Water Defence Lines. == Fortifications ==

. island. Locks • Inundation lock southern Beemsterringdijk () Barracks • Amsterdam Cavalry Barracks • Oranje-Nassau Kazerne Other • • • ==See also==