1757 - Siege of Schweidnitz

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The siege took place from October to November 1757

Description of Events

Prelude to the Siege

During the invasion of Silesia, taking advantage of the absence of Frederick II with part of the Prussian army confronting the Franco-Imperial invasion of Saxony and of the retreat of Bevern towards Breslau (present-day Wroclaw), Prince Charles resolved to capture the strong fortress of Schweidnitz (present-day Swidnica) which contained one of the most important Prussian magazine in Silesia.

Map

The fortress of Schweidnitz (actual Swidnica) is located in Silesia, at an important crossroad linking Breslau, Glatz, Landeshut and the axis Bunzelwitz-Striegau-Liegnitz. In the vicinities of the city, to the east of it, ran the Weistritz river with sandy banks and marshes all along its course. The Weistritz river separates Schweidnitz from its suburb of Kletachkau. To the south of the fortifications of the city lays the suburb of Schreibendt and the mill known as the Neue Mühle, on the banks of a tributary of the Weistritz: the Bögen Wasser.

The city of Schweidnitz was a fortified place which Frederick II improved from 1747 to 1756 through continuous series of works. The works were finished just for the outbreak of the Seven Years' War. Outer works were added to the walls dating from previous periods. Some of these outer works were as far as 500 m. from the city walls. The concept was new and revolutionary. It relied on defensive zones taking advantage of the lay of the land in front of the works and creating areas of cross fire. This approach was an innovation compared to Vauban's theory basing the defence on a continuous rampart completely conditioning the dispositions of the outworks. Developed by the same Frederick, this brilliant innovation, often copied in the military architecture of the XVIIIth century, allowed for a more economic use of fortifications without the huge dispersion of manpower and artillery necessary to defend the extensive perimeter of a city, and the vast construction and maintenance expenses.

The Austrians, who eventually became masters of the fortress, did not really grasp the modernity of its structures and linked the outworks with fieldworks to constitute continuous fortifications.

Map of the fortress of Schweidnitz in 1757.
Source: Kriege Friedrichs des Grossen, volume III by the German Grosser Generalstab

The role of stronghold was assumed by a kind of star or zigzag shaped fortification known as a sternschanze, consisting of a small central irregularly shaped pentagon with a three-pointed base facing the town. A small place of arms occupied the inside of this sternschanze with ramps leading to the platform protected by a parapet; a ditch separated the central redoubt from the external star-shaped curtain wall. The base of the curtain wall ran parallel to the walls of the five-pointed central redoubt whose three longer walls were parallel to those of the curtain wall and its two smaller ones ran opposite to its base. The height of the outer curtain wall allowed to fire from the central redoubt. The zigzagged outer curtain wall was fitted with a ditch and a counterscarp, a covert way and a glacis. In the inner angle between two bastions, covered caponnieres with loopholes for enfilade fire crossed the ditch to link the curtain wall to the redoubt. The central redoubt was armed with 15 heavy guns deployed evenly in three batteries placed at the extremity of each point.

Each sternschanze had its own powder magazine, barracks for its garrison and magazines providing for a certain autonomy for these isolated forts. The entrance was located at the base and accessed through a covert way. The parapet of this covert way, the caponnieres and the base of the curtain wall in the ditch were reinforced by palisades and breastworks of fallen trees. A vast network of countermine galleries existed and was later improved by the Austrians after the capture of the fortress.

Around the town of Schweidnitz there were four of these forts and other minor fortifications. Oriented to the south, the Bögen Fort (star-shaped) then, proceeding counter-clockwise, the Wasser Redoubt (an arrow shaped ravelin) oriented to the southeast, followed by the Wasser Fort in the shape of an irregular hexagon oriented to the east. To the north of this latter fort there was a ravelin (arrow shaped), then the Galgen Fort (star-shaped) which constituted the northeast angle of this ring of forts. To the northeast of it, isolated at a certain distance, there was a small arrow shaped redoubt. Oriented to the north, the Kirchen Redoubt (arrow shaped). At the northwest angle of the ring of fortifications, the Jauernicker Fort (star-shaped) reinforced by the Jauernicker Flèche (a ravelin). Then followed, oriented to the west, the Jauernicker Redoute (arrow shaped), the Garten Fort (star-shaped); the interval between the Garten Fort and the Bögen Fort was occupied by the Garten Redoubt (arrow shaped).

The Wasser Redoubt and the Wasser Fort overlooked the Weistritz river flowing to the southeast of Schweidnitz.

The Siege

Map of the siege of Schweidnitz from October 24 to November 12 1757.
Source: Kriege Friedrichs des Grossen, volume III by the German Grosser Generalstab

On October 26, Nádasdy with 20,000 men began the siege of the fortress of Schweidnitz. Meanwhile, Prince Charles covered the approach with 60,000 men to prevent any intervention by Bevern. The Austrian army was posted in front of Bevern's army encamped at Breslau on the opposite side of the Lohe, between Strachwitz and Masselwitz (present-day Maslice) with a reserve between Goldschmieden (present-day Zlotniki) and Stabelwitz (present-day Stablowice). The village of Neukirchen was to its front and was surrounded by strong entrenchments.

The fortress of Schweidnitz was garrisoned by 6,000 men under the command of Seers, governor of the place, and Grumbkow, his second in command.

On October 27, Nádasdy opened his trenches. Even though Frederick II was still very busy in Saxony, he made instant arrangement for Silesia. Prince Henri was ordered to maintain the Saale and guard Saxony. Similarly, Marshal Keith was ordered to cross the Erzgebirge through Marienberg and Passberg with a small corps and to advance into Bohemia to draw the attention of the Austrians to that side.

On November 10, Nádasdy third parallel was finished. The garrison had made several successful sorties, and though part of the town had been destroyed by bombardment, the Austrians had not yet gained a single outwork.

During the night of November 11, impatient at making so little progress, Nádasdy resolved to risk a coup-de-main and attacked by general assault the redoubts surrounding the place, two of which were taken.

Bombardment of Schweidnitz - Copyright: Ing. Jiří Sissak Ph.D, reproduced with the kind authorisation of the Monastery Ordo Sancti Benedicti, Broumov, Czech Republic

On November 12, a few days after his victory at Rossbach, Frederick took 13,600 men (19 bns, 28 sqns) of his own army and marched from Leipzig. He passed by Torgau, Muhlberg, Grossenhayn, Bautzen and Weissenberg. He then crossed the Queiss and the Bober as fast as he could to relieve Schweidnitz.

On November 14, Seers and Grumbkow capitulated and surrendered themselves and garrison as prisoners of war.

On November 18 at Grossenhain, Frederick learned that Schweidnitz had capitulated on November 14. This was a very brief resistance for such a strong fortress.

Outcome

Immediately after the capitulation of Schweidnitz, Nádasdy, leaving a garrison of 3,000 men in the fortress, joined Prince Charles bringing the united Austrian army to 80,000 men. Nádasdy's corps deployed on the right wing between Bethlern and Oppenau. The Austrians could now concentrate their attention on Bevern's corps defending Breslau.

Order of Battle

Austrian Order of Battle

Commander-in-chief: General of Cavalry Franz Leopold von Nádasdy auf Fogaras

Summary: 20,000 men

Prussian Order of Battle

Commander-in-chief: Seers

Summary: 6,000 men

References

This article incorporates texts from the following books which are now in the public domain:

  • Anonymous, A Complete History of the Present War, from its Commencement in 1756, to the End of the Campaign, 1760, London, 1761, pp. 223-226, 236-240
  • Archenholz, J. W., The History of the Seven Years War in Germany, translated by F. A. Catty, Francfort, 1843, p. 127
  • Carlyle T., History of Friedrich II of Prussia vol. 18
  • Donnersmarck, Victor Amadaeus Henckel von, Militaerischer Nachlass, Karl Zabeler, 1858
  • Plan of the Austrian siege of Schweidnitz in 1757, published in 1761 now in a museum in Berlin (ref. no. X2322-3)
  • Tielke, J.G.: Beytrage zur Kriegs-Kunst und Heschichte des Krieges von 1756 bis 1763, Vol. 4, Freyberg, 1781

Acknowledgments

Carlo Bessolo for the description of the fortress in the "Map" section

Krzysztof Czarnecki for the orders of battle