Construction of the Fort Friedrichsburg or Feste Friedrichsburg began in 1657 during the Second Northern War by the order of Frederick William of Brandenburg-Prussia. The only remnant of the former fort is the Friedrichsburg Gate. The fort was built in place of a tollhouse on the southern shore of the Pregel River at the western edge of Königsberg. It was included within the new ring of Königsberg fortifications constructed from 1626–34. Districts neighboring the fort were Vorstadt to the east, Nasser Garten to the southwest outside of the city walls, and Lastadie to the north across the river. Construction of the fort was resented by the constituent towns of Königsberg, especially Kneiphof.
Friedrichsburg was designed by Christian Otter, court mathematician and Albertina professor. Friedrichsburg's position allowed its cannons to defend the city from the west, monitor incoming traffic from the Frisches Haff, and suppress civil uprising. The fort originally consisted of earthwork, bricks, and ditches. The square-shaped structure included four bastions, nicknamed Smaragd, Perle, Rubin, and Diamant.
Initially only the northeastern bastion contained a cavalier and ravelin. Later additions included ravelins along the western and southern fronts, a cavalier along the southwestern bastion, and a covered way along the counterscarp. These additions were possibly completed during the occupation of Königsberg by the Imperial Russian Army in the Seven Years' War (1758–62). The additions were not visible on Valerianus Müller's plan from 1815.
The interior of the fort contained a command building, lodging, supplies, and prisons. It had a small permanent garrison of about 150 men, but could host a stronger force if need be. A small church, constructed in 1671, served as the garrison church until 1816. An armory was completed in 1796, but dismantled in 1892.
Peter I of Russia studied the fort in 1697 while touring Europe. The fort was used as a state and military prison until 1825; Ludwig Yorck von Wartenburg was imprisoned there for insubordination from 1780–81. The Friedrichsburg Gate was completed during the reign of King Frederick William IV of Prussia. The fort was remodeled in 1852 during the reign of King Frederick William IV of Prussia, with construction of the stately Friedrichsburg Gate, new walls, and expansion of the citadel with four round towers. By the end of the 19th century, however, the fort was used only for military storage.
To allow construction of new tracks for Königsberg's goods station, Friedrichsburg was sold to the Prussian Eastern Railway on 23 August 1910 and subsequently dismantled. Segelclub RHE moved from Friedrichsburg to Contienen in 1914.
The site was used for storage and automobile exhibitions after the change of German Königsberg to Russian Kaliningrad resulting from World War II. It is being restored during the 2010s and is part of the Museum of the World's Oceans.References:
The moated castle at Beersel is one of the few exceptionally well-preserved examples of medieval fortifications in Belgium. It remains pretty much as it must have appeared in the 15th century. Remarkably, it was never converted into a fortified mansion. A visitor is able to experience at first-hand how it must have felt to live in a heavily fortified castle in the Middle Ages.
The castle was built in around 1420 as a means of defence on the outer reaches of Brussels. The tall, dense walls and towers were intended to hold any besiegers at bay. The moat and the marshy ground along its eastern, southern and western edges made any attack a formidable proposition. For that reason, any attackers would have chosen its weaker northern defences where the castle adjoins higher lying ground. But the castle was only taken and destroyed on one occasion in 1489, by the inhabitants of Brussels who were in rebellion against Maximilian of Austria.
After being stormed and plundered by the rebels it was partially rebuilt. The pointed roofs and stepped gables are features which have survived this period. The reconstruction explains why two periods can be identified in the fabric of the edifice, particularly on the outside.
The red Brabant sandstone surrounds of the embrasures, now more or less all bricked up, are characteristic of the 15th century. The other embrasures, edged with white sandstone, date from the end of the 15th century. They were intended for setting up the artillery fire. The merlons too are in white sandstone. The year 1617 can be clearly seen in the foundation support on the first tower. This refers to restorations carried out at the time by the Arenberg family.
Nowadays, the castle is dominated by three massive towers. The means of defence follow the classic pattern: a wide, deep moat surrounding the castle, a drawbridge, merlons on the towers, embrasures in the walls and in the towers, at more or less regular intervals, and machiolations. Circular, projecting towers ensured that attacks from the side could be thwarted. If the enemy were to penetrate the outer wall, each tower could be defended from embrasures facing onto the inner courtyard.
The second and third towers are flanked by watchtowers from which shots could be fired directly below. Between the second and third tower are two openings in the walkway on the wall. It is not clear what these were used for. Were these holes used for the disposing of rubbish, or escape routes. The windows on the exterior are narrow and low. All light entering comes from the interior. The few larger windows on the exterior date from a later period. It is most probable that the third tower - the highest - was used as a watchtower.