Fort Friedrichsburg

Fort Friedrichsburg or Feste Friedrichsburg was a fort in Königsberg, Germany. The only remnant of the former fort is the Friedrichsburg Gate (Russian: Фридрихсбургские ворота, German: Friedrichsburger Tor) in Kaliningrad, Russia.

Construction of the fort began in 1657 during the Second Northern War by the order of Frederick William of Brandenburg-Prussia. 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.

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