Poznań Fortress

Poznań Fortress, known in German as Festung Posen (Polish: Twierdza Poznań) was a set of fortifications in the city of Poznań (German: Posen) in western Poland, built under Prussian rule in the 19th and early 20th centuries. It represents the third largest system of its kind in Europe.

The first set of fortifications was a tight defensive ring around central Poznań, including the main citadel called Fort Winiary (now the Cytadela park). Construction of these fortifications began in 1828. Later, beginning in 1876, an outer defensive ring was built around the perimeter of the city, consisting chiefly of a series of "forts", which mostly still survive.

The term Festung Posen was also used by the Nazi German occupiers during the Red Army's advance in the closing phases of the Second World War, to refer to Poznań's status as one of the "strongholds" (Festungen) which were to be defended at all costs. It fell in the Battle of Poznań (1945), with Fort Winiary the last point of resistance.

Poznań (Posen) came under Prussian rule with the Second Partition of Poland in 1793. Its medieval city walls were obsolete by that time, and were mostly taken down in the early 19th century to facilitate the city's growth. The Prussian authorities first made plans to build new fortifications in December 1815. The city lay on the shortest route from the border with Congress Poland (and hence with the Russian Empire) to Berlin, and was also an important point on the route from West Prussia to Silesia; therefore, according to General Karl von Grolman, its fortification would show that Prussia had no intention of giving up those lands, and would defeat the "continuous intrigues and plotting" on the part of the Poles. A preliminary plan sketched by Grolman on 9 July 1817 provided for fortification of Winiary Hill north of the city, as well as the area of St. Kazimierz's Church in Śródka to the east. Army engineers added to these plans a weir on the river Warta (Warthe), which would enable the river to be used as part of the defences.

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