Ravelin AnselmCoat of ArmsBastion MartinBastion Franz Ravelin Peter

Coat of Arms 

Bation Martin

Bastion Franz 

Ravelin Anselm

Ravelin Peter



Artillery barrack


Bastion Gabriel

Bastion Johann


Bastion Kilian


Barrack A


Church of St. Peter




Defensible Barrack


Piece Time Powder Magazine


Bastion Martin


Mine Gallery


Bastion Philipp


Wartime Powder Magazine


Early drawing of Fort Cyriaksburg


1850's drawing of the Fort


Fortress Petersberg

The Fortress  Petersberg was originally constructed by the principality of Kur-Mainz and later came under Prussian control. Located right in the center of the capital city of the state of Thuringia. 

The fortress is considered one of the largest and best preserved of its kind in Europe and construction  was started in 1665 by orders of the Elector and Archbishop Johann Philipp von Schönborn in the new Italian style. Build to protect this part of the electrorate against any attack by the Protestant powers. In later years the strategic importance of the Citadel was realized by the Prussian state and for a short time by the French emperor Napoleon. Used by the military until the late 1980’s.

In the 1990’s  the state of Thuringia and the city of Erfurt begun a very impressive restauration program of the fortress.

The foundation for the new fortress was laid in June 1665. Initially known as Johann Philipp Citadel. Thus began the first of three construction periods.

Construction begun in 1669 under the direction of engineer Wilhelm Schneider. First constructed were the four bastions facing the city (bastion Martin, Philipp, Leonhard and Kilian) and the gate and commandant building designed by Antonio Petrini. Mine galleries were constructed in the new fortress walls which were also connected with the old city fortifications. Between 1675 and 1700, the four remaining bastions Johann, Michael, Gabriel and Franz, the three barracks buildings including the two ravelins Lothar and Anselm. Ravelins are works placed in front of a curtain wall (wall connecting two bastions) to protect the wall from any attack.  Construction  was repeatedly delayed and it took almost 40 years to finish the ring of walls and bastions.

Thus ended the first construction period (1665-1702).

In the 17th and 18th Century the barracks of the Petersberg housed the 500 to 800 men strong garrison. During the Great Northern War (1700-1721) Swedish troops threatened the area of Erfurt. .

For this reason Mainz decided to modernize the Petersberg. The well known military architect Johann Maximillian von Welsch was employed. Following  the example of the great French military engineer Vauban he attached particular importance to the strengthening of the ditch defenses and the construction of new fore-works. This led to the construction of two new lunettes and two more raveling (Wilhelm and Peter), a short pieces of Wall (1708) and a new horn work in front of the bastion Gabriel (1725-1728). Ravelin Peter protected the approaches to the fortress gate. Welsch presumably based his work on the early blueprints of the fortress.

The ditch was enlarged and expanded around the whole fortress and equipped with a staggered palisade system. The counter-mine system was expanded. To control the access to the fortress gate better a guard house was constructed in front of ravelin Peter (1735).  With the completion of the two gun casemates in the bastions Philipp and Johann the second period (1707-1737) ended.

The high financial costs of maintaining the buildings and military installations, the new military developments in the 1770s led to considerations in the administration of the electorate. The thoughts went even so far to dismantle the fortress. But with the outbreak of the War of the Bavarian Succession (1778-1779), everything changed. The fortress with its external works continued to be used and makeshift repairs were undertaken.

Under Prussian rule 1802 to 1871

According to the Franco-Prussian treaty of 1802,  Prussia received in compensation for the lost territories on the left bank of the Rhine, among other things the Eichsfeld and Erfurt. In 1803 Prussian troops under Generals von Wartensleben occupied the city and the fortress.

Already back in March 1803 the new owners dissolved the Benedictine monastery of St. Peter and Paul to create more room for the new much stronger garrison of the fortress. In addition, because of its important geopolitical position, the fortress was to be modernized. But initially only small repairs were undertaken. The situation only changed with the outbreak of war between France and Prussia in 1806, when construction work resumed. Work focused on the erection of new palisades, the construction of new fieldworks and replenishing the supplies for the garrison.

Siege of the citadel by the Allies 1813/1814

After the defeat at the Battle of Jena Auerstedt 14 October 1806 parts of the defeated Prussian army fled to Erfurt. Already a day later the Prussian troops surrendered on the orders of Prince Wilhelm von Oranien.  Around 10000 Prussians were taken prisoner.

On the 23th of June 1807 Napoleon arrived in Erfurt. A year later in 1808 at the time of the Fuerstenkongress held in Erfurt, Napoleon and Tsar Alexander I visited the fortress. In the following years Napoleon ruled with an iron fist over Europe. Changes appeared when French troops had to fight for survival in Spain. It was the beginning of the end. The problems for Napoleon did not get better with the beginning of the Russian campaign in 1812 which, ended with the destroying of the Grand Army.

Already on the 24th of February 1813 the Petersberg was prepared for a defense against the Allied armies. Repairs were undertaken to improve the defensive capabilities of the fortress. Many of the buildings were provided with bomb-proof roofs, the glacis was renewed and new traverses constructed. Supplies to last the 2000 men garrison for 6 month and fodder for the many horses were brought in and stored in the church of St.Peter. Napoleon visited Erfurt for the last time in April and October 1813. 

The Battle of the Nations (16 to 19 October 1813) sealed the downfall of Napoleon. Part of the French army fled after the fight to the city of Erfurt. Here a new defense was to be organized. Marshall Alexander Dalton was appointed to be in charge of the defence of the fortress. He closed all the gates and shops of the city on the 25th of October.

After three days a Prussian army 34900 men strong, consisting of the Second Army Corps under Lieutenant-General Graf Kleist von Nollendorf and Austrian and Russian army units had closely surrounded Erfurt. The troops were quartered in the surrounding villages. A siege battery was emplaced near the Schwedenschanze. In an attempted to improve the defense the French attacked and destroyed the village of Daberstedt.

On the 4th of November 1813 the French occupiers were asked to hand over the city of the fortress citadel without a fight. But Marshal Alexander Dalton said: The emperor has given me the place Erfurt and entrusted me with  the defence.I will meet his expectations, as I do my duty. I cannot embark on a different arrangement. On the same evening, the village of Ilversgehofen was attacked by the French with 1500 men. Attacks like that forced the combined army into some quick actions.  A few days earlier a council of War Council decided o start the bombardment of the Petersberg.

On the evening of the 5th of November two Austrian and Russian batteries were emplaced at the village of Marbach, a Prussian battery was emplaced at the Steigerwald. On November 6th at six o’clock in the morning the bombardment of the fortress started. Before long, the first building on the Petersberg burned. The convent, the old guard-house, part of the church of St. Peter church and many houses around the Domplatz were destroyed by the raging fires.

Despite the strong bombardment and destruction the French were not ready to surrender. It came to a ceasefire, which was gradually extended. The French moved out of the city and retreated to the Petersberg. While the French capital of Paris was taken by allied troops in April of 1814, the Petersberg was still in French hands. Finally on May 5th May 1814 Marshal Alexander Dalton handed over the citadel to the allied troops after he had received orders from the French government  to do so. Finally 1700 French soldiers with 6 guns marched out to Strasbourg.

The Congress of Vienna (1814-1815) led to a restructuring of Europe.

 The Prussian government decided to modernize the Petersberg and the Cryiaksburg and make them first rank fortresses. Thus began the last construction  period (1815-1831).

In this first period damaged buildings and military installations were repaired. Furthermore between 1823 – 1825 gun caponnieres were constructed to defend the ditch of the fortress. Any of the new works was based on the neupreußischen System. Near the front of bastion Martin a Kanonenhof was constructed. Between 1828 – 1831 a defensible barrack was constructed on the aerial of the completely destroyed monastery. The new barrack was also an artillery position  which also stopped the view from the north to the top plateau of the fortress. It also divided the fortress into tow defensible sections.

For the storage of powder piece time powder magazines were constructed in 1822 on the ravelin Anselm and on the horn work. In 1830 war powder magazines were constructed  on bastion Franz and Philipp. As a final measure seven advanced forts were to be constructed, but only Fort I in front of the Auerschanze and Fort II on the Schwedenschanze were build between 1866 – 1869. This self detained heavily fortified outer works were to prevent the shelling of the main fortress.  In addition to the modernization of the works changes were undertaken in the garrison. expanding the citadel, there were also changes within the crew. In 1860 a new regiment was formed, the Thuringian Infantry Regiment. Nr. 71. Until the end of WWI it was stationed at the defensible barrack on the Petersberg.

From Empire to the end of WWII (1871 – 1945)

With the founding of the German Empire in 1871 many of the fortresses lost their importance. In 1873 the Petersberg on orders of the Emperor Wilhelm I.,  was declassified as a fortress.

The luck of money only allowed to take down the two ravelins, Peter and Wilhelm, the Hornwerk and the cavaliers.  When a new access road was constructed part of bastion Gabriel was taken down and Lunette I completely removed. Between 1912 to 1914 new buildings were erected. The Hornwerk Barrack and a military detention center were constructed.

In consequence of the Peace Treaty of Versailles many military installations were closed down.  Utnil 1933 the barrack buildings were used by the police and by the Free Corps Thuringia. In 1921, the Lauentor road was completed, it separated the point of the bastion Martin from the fortress..

In the period up to 1945 the Petersberg arsenal was used for military purposes again. Between 1936 and 1938 part of the barracks were used as quarters for the newly formed motorized infantry regiment No 71 and between 1938-1943 was used as an administrative office of the armed forces. Furthermore, in the old commandant house the military court 409 was located. The underground counter-mine system was used as an air raid shelter.

In April 1945 the city and fortress were occupied by the Americans. With the establishment of the GDR on October 7th police and military came back to the Petersberg.

The building before the bastion Johann were used as a motor pool of the SD and the barracks were used by the NVA. From 1963 the Petersberg was given back to the city and the site was partially open to the public. With the turn of 1989/1990 the city of Erfurt established a building works on the Petersberg. The following restoration program created a beautiful example of a wonderful historic fortification a great piece of German history. The upper barracks, the military detention center and the Schirrmeisterhaus are used as residential residences and for office spaces.

 The Citadel Petersberg is now a popular historic site, which offers also a panoramic view over the city.



24 pounder firing