Mainz Citadel: A Bastioned Fortress on the Jakobsberg
Site at a Glance
- Rating
- 4.5
- Popularity
- Medium
- Country
- Germany
- Primary era
- Early Modern
- External website
- Open
- Eras represented
- Classical, Early Modern, Modern
- Civilizations
- German, Habsburg, Holy Roman Empire, Roman
- Site type
- Military
- Remains
- Citadel
On this page17 sections
History
Mainz Citadel is a fortified complex in Germany that developed on the Jakobsberg at the edge of Mainz’s Old Town. Its present form grew from the seventeenth-century expansion of an earlier fortress, creating a bastioned stronghold that protected the city and later served military, educational, civic, and cultural purposes.
The Jakobsberg and the Schweickhardtsburg
The Jakobsberg had been occupied by the Benedictine Abbey of St. Jacob since its foundation in 1050. The hill also preserved traces of Mogontiacum, the Roman settlement that developed into Mainz and served as the capital of Upper Germania. Halfway up the slope, the remains of the Roman stage theater were still visible.
Because the hill lay beyond Mainz’s defensive-wall circuit and had only light fortifications, it formed a vulnerable gap. An enemy could use the position to raid the city or bombard it. To close this opening, the Schweickhardtsburg was built between 1620 and 1629 under the supervision of the cathedral canon Adolph von Waldenburg. The irregular pentagonal fortification took its name from the ruling elector, Johann Schweikhard von Kronberg.
In 1655, Elector Johann Philipp von Schönborn began a wider modernization of Mainz’s defenses with bastions of French type. A bastion is a projecting fortified platform designed to provide flanking fire along the walls. As part of this work, the Schweickhardtsburg was enlarged and transformed from an earthen fortification into the regular quadrangular citadel that forms the basis of the present complex.
Expansion and the Siege of Mainz
The new fortress incorporated older features of the Jakobsberg. The monastery of St. Jacob and the Drususstein remained within the defenses. The Drususstein is a Roman cenotaph, or commemorative monument that does not necessarily contain the person’s remains, associated with the Roman military commander Drusus. In antiquity, the hill was also connected with the public cult of Drusus and with gatherings of representatives of sixty Gallic tribes.
The fortress gate facing the city was built in 1660 under Antonio Petrini. In 1696, Elector Lothar Franz von Schönborn ordered a building for the citadel commander above the gateway, incorporating the earlier structure into the new arrangement.
During the Siege of Mainz in 1793, intense Prussian bombardment largely destroyed St. Jacob’s Abbey. The surviving abbot’s and guest buildings were then used for military purposes. A Baroque garden in the southern part of the courtyard was still shown on a plan of 1804, preserving evidence of the former internal landscape after the abbey’s destruction.
Telegraph station, fortress barracks, and wartime uses
From May to October 1813, the citadel served as a station on the optical telegraph line to Metz. After Mainz became a fortress of the German Confederation in 1816, Prussian and Austrian troops occupied the complex and used it as a barracks. The German Confederation was a nineteenth-century association of German states established after the Napoleonic Wars, and its fortress at Mainz was operated by forces from several of those states.
The Austrian Citadel Barracks was added in 1861 as a bombproof building. A small adjacent structure served as a casino and kitchen. In 1914, a double-company barracks was erected, requiring the removal of the monastery’s last remains. Architectural elements from the former abbot’s and guest buildings were reused in the new barracks.
The Treaty of Versailles in 1919 required the dismantling of the fortifications in and around Mainz, bringing the citadel’s long military history to an end as a fortress. From 1933 to 1936, before and during the Nazi period, the complex housed the Rhein-Main Education Center, a regional institution for the ideological training of teachers and pupils. During both world wars, it was also used as a prisoner-of-war camp. From 1940 until near the end of the Second World War, it housed Officers’ Camp XII-B, known as Oflag XII-B. Oflag was the German abbreviation for an officers’ prisoner-of-war camp.
During the Second World War, the casemates beneath Bastion Drusus were converted into air-raid shelters. A casemate is a vaulted or enclosed military chamber that can serve for storage, defense, or shelter, and these spaces provided refuge for parts of Mainz’s population during bombing.
Postwar civic and cultural history
After the Second World War, French occupation authorities seized the citadel and retained it until 1955. In 1950, the French administration established the Paul Tirard School there for the children of French military and civilian personnel. In the 1960s, the complex housed Mainz’s commercial vocational school until the school moved to a new building on the Hartenberg.
The City of Mainz has owned the site since 1955. It now accommodates municipal offices and cultural institutions. Mainz Citadel has been protected as a cultural monument since 1907. Since the mid-1980s, the southern trench has also been protected as an anthropogenic biotope and landscape feature of nationwide importance. An anthropogenic biotope is a habitat substantially shaped or created by human activity. In October 2015, the complex received the UNESCO Hague Plaque, identifying it as cultural property protected under the laws governing cultural property during armed conflict.
Since 1975, the citadel has hosted the annual OpenOhr Festival during the Pentecost weekend. The youth-culture event combines discussion forums, workshops, cabaret, and live concerts, giving the former fortress a continuing civic and cultural role.
Remains
Mainz Citadel occupies an enclosure approximately 340 by 320 metres on the Jakobsberg. Its regular quadrangular plan reflects the transformation of the earlier irregular pentagonal Schweickhardtsburg. The defenses are organized around projecting bastions connected by curtain walls, the main walls joining the fortified projections. The surviving complex brings together early modern fortifications, later military buildings, a Roman monument, wartime shelters, and the protected southern trench.
Bastioned defenses and gateways
Named bastions
Bastion Germanicus stands on the south side and Bastion Alarm on the east. Both bear the date 1659. Bastion Tacitus occupies the north and bears the date 1661. These dated structures belong to the regular bastioned fortress created during the enlargement of the Schweickhardtsburg in the second half of the seventeenth century.
Fortress gate and commander’s building
The fortress gate lies in the northeastern curtain wall between Bastions Germanicus and Alarm. It bears the date 1660 and faces the city. The gateway was incorporated into the commander’s building constructed above it in 1696, allowing the earlier entrance to remain part of the later architectural composition.
Roman monument and former monastic area
Drususstein
Bastion Drusus contains the Drususstein, a Roman cenotaph associated with Drusus. The monument remained in place when the seventeenth-century fortress expanded around it. Its presence preserves a physical connection between the Roman history of Mainz and the later military history of the Jakobsberg.
Abbey remains and reused elements
St. Jacob’s Abbey once stood within the fortress. Bombardment during the Siege of Mainz in 1793 destroyed most of the abbey, while the surviving abbot’s and guest buildings were later put to military use. The monastery’s last remains were removed when the double-company barracks was built in 1914, but architectural elements from those earlier buildings were incorporated into the new structure.
Barracks, shelters, and courtyard landscape
Citadel Barracks
The Austrian Citadel Barracks dates from 1861 and was built as a bombproof structure. A small neighboring building served as a casino and kitchen. Together with the double-company barracks added in 1914, these buildings represent the nineteenth- and early twentieth-century conversion of the fortress into a military accommodation complex.
Drusus shelters
The casemates beneath Bastion Drusus were converted into air-raid shelters during the Second World War. Their later form reflects the adaptation of earlier defensive chambers to the requirements of wartime civilian protection.
Southern courtyard garden and trench
A Baroque garden occupied the southern part of the courtyard, as shown on an 1804 plan. The southern trench survives as a protected anthropogenic biotope and landscape feature. Its form and habitat reflect the long interaction between fortress construction and the landscape of the Jakobsberg.
Present cultural use
Building D, positioned in front of the Drususstein, houses the Mainz Historical Museum. Municipal offices and other cultural institutions occupy parts of the complex, while the surviving defenses, barracks, Roman monument, shelters, and trench preserve the physical layers of the citadel’s development.
