The fortifications of Frankfurt were a system of military defences of the German city of Frankfurt am Main which existed from the Middle Ages into the 19th century. Around 1000 the first city wall was built. It enclosed the area of what is now the Königspfalz in modern Frankfurt. In the twelfth century the settlement expanded into what is now Altstadt. For its protection an additional wall, the Staufenmauer, was erected. Starting in 1333, the Neustadt suburb developed north of the Altstadt and was encompassed by an additional wall with five gates. In the fifteenth century, a "landwehr border" was created around the entire territory of the Free City of Frankfurt. Beginning in 1628, the medieval city wall was developed to form a bastion fortress under the municipal architect Johann Dilich.
After its defeat in the Kronberg Feud in 1389, Frankfurt consistently avoided military conflicts and relied on its diplomatic relationships throughout the Holy Roman Empire and beyond. For this reason, the city's fortifications, during the nearly eight centuries of their existence, have only had to stand a siege onceduring the Second Schmalkaldic War, in July 1552. During the eighteenth century the fortifications lost their military significance and hindered further expansion of the city: the walls were torn down between 1806 and 1818. Their former position now forms a green belt around the inner city. Various components of the fortifications are preserved, including: seven towers, among them the Eschenheimer Turm; a 200-metre stretch of the Staufenmauer; remnants of the landwehr border; and a 90-metre section of a casemate, discovered in 2009, which once formed part of the baroque bastion fortress.
First city wall
Königspfalz Frankfurt Frankfurt's oldest fortifications were created to protect the Carolingian palace (German: Karolingische Pfalz) which was first recorded in 822. Until the 1930s it was thought to have been a predecessor of today's . In 1936, Heinrich Bingemer proved by excavations that this originated in the Hohenstaufen era, and concluded that the site of the Carolingian palace may have been located further to the east. In 1953 archaeological excavations in the core of the historic town, made possible by the bombing and destruction of Frankfurt in World War II, revealed remnants of the historic palace, west of Frankfurt Cathedral, in the basement of the Haus zur Goldenen Waage.Ernst Mack: Von der Steinzeit zur Stauferstadt. Die frühe Geschichte von Frankfurt am Main. Knecht, Frankfurt am Main 1994, , S. 121 ff.
The palace was situated on a flood-safe elevation in the east of the Altstadt. It was originally an island between the southern Main and the northern Braubach, a river which silted upKarl Nahrgang: Die Frankfurter Altstadt. Eine historisch-geographische Studie. Verlag Waldemar Kramer, Frankfurt am Main 1949, S. 10 (Fußnote); nach Pollenanalysen und archäologischen Funden der Altwasserläufe von Rhein und Neckar. in the first Christian millennium and was canalisedJohann Georg Battonn: Oertliche Beschreibung der Stadt Frankfurt am Main – Band I. Verein für Geschichte und Alterthumskunde zu Frankfurt am Main, Frankfurt am Main 1869, S. 72–76; 1468 erfolgte zwecks besserer Kanalisierung eine Auskleidung mit Holzbohlen, ab 1558 die Ausmauerung und Einwölbung auf Kosten der Anwohner, wobei letztere Maßnahme erst im frühen 19. Jahrhundert vollendet war. during the Medieval period. South of the palace was the ford (German: "Furt"), which gave Frankfurt not only its name but also its reason for existence. West of the palace, a swampy lowland ran across today's Römerberg to the Main.
Archaeological findings
Excavations
When parts of the wall were brought to light during the construction of the Dompfarrhaus on the northern Domplatz in 1827, and later in the cellars of houses in the western Altstadt area, Ulrich's description of the early medieval fortification was considered to be confirmed. During the construction of the Braubachstrasse through the Altstadt from 1904 to 1906 Christian Ludwig Thomas, an architect commissioned by the Historical Museum of Frankfurt, was able to confirm the northern and north-western position of the wall by sinking over 50 excavation shafts.Christian Ludwig Thomas: Der nordwestliche Zug der ersten Stadtmauer von Frankfurt a. M. In: Einzelforschungen über Kunst- u. Altertumsgegenstände zu Frankfurt am Main. Band 1 (mehr nicht erschienen), Verlag von Joseph Baer, Frankfurt am Main 1908, S. 163.
From 1953 to 1955, archaeologists continued the research and inspected the city wall in the area of the Hauptzollamt (today's Haus am Dom).Magnus Wintergerst: Franconofurd. Band I. Die Befunde der karolingisch-ottonischen Pfalz aus den Frankfurter Altstadtgrabungen 1953–1993. In: Egon Wamers, Archäologisches Museum Frankfurt im Auftrag des Dezernats Kultur und Wissenschaft (Hrsg.): Schriften des Archäologischen Museums Frankfurt 22/1. Archäologisches Museum Frankfurt, Frankfurt am Main 2007, S. 96. Archaeological studies of the area of the Saalhof from 1958 to 1961 by Otto Stamm proved the position of southern wall section along the Main and a short western part of the wall below the Saalgasse.Otto Stamm: Der königliche Saalhof zu Frankfurt am Main. Sonderdruck aus den Schriften des Historischen Museums Frankfurt am Main XII, Verlag Waldemar Kramer, Frankfurt am Main 1966, S. 16; vgl. auch Beilage 2. The last excavations directly connected with the historic wall were made in 1976, again on the premises of the Dompfarrhaus. Archaeological research to establish the south-eastern and eastern location of the wall has not yet taken place. The stratigraphy in the area of the Römerberg was presumably significantly damaged by construction works in the Medieval period and destroyed by the construction of an underground car park in the 1970s, reducing the amount of information obtainable in this area.
Archaeological record
The appearance and the composition of the wall are reliably known.Christian Ludwig Thomas: Die erste Stadtmauer von Frankfurt a. Main. In: Bericht über die Fortschritte der römisch-germanischen Forschung. Band 1, Verlag von Joseph Baer, Frankfurt am Main 1904, S. 75–78. On average it had a thickness and height of . For what are assumed to be psychological reasons,Wintergerst, S. 98. it was thick on the Main side to the south. The fortification was made up of coarse gravel and rough-hewn quarried stone, but also contained higher-quality pieces of sandstone from Vilbel and basalt, possibly taken from demolished Roman structures. The material was relatively crude, and only on the outside does it have an orderly opus spicatum structure. The mortar was poor quality, consisting of loam mixed with plant fibres and animal hair. According to Thomas, the foundation was so deficient that the wall tilted away from the vertical. Thomas also uncovered sections of wall that had apparently been repaired using higher quality mortar, demonstrating the importance of the wall: Despite its significant flaws, it was apparently considered to be important enough for restoration.
Thomas attributed the initial creation of the wall to the 9th century and considered Louis the German to have given the orders for its construction. He based this on Pingsdorf ware found close to the wall, and because Pingsdorf ware was thought to have been Carolingian.Thomas 1904, S. 77. During the excavations in 1976, a made of coarse mica was recovered. This type of pottery came into use at the end of the 10th century, and Pingsdorf ware is currently considered to be a post-900 development, leading to the conclusion that the wall may not have been a Carolingian construction, but an Ottonian one. Additionally, an official document from 994 describes the city as "castello" (a fortress),Johann Friedrich Boehmer, Friedrich Lau: Urkundenbuch der Reichsstadt Frankfurt. Band I 794–1314, J. Baer & Co, Frankfurt am Main 1901–1905, S. 10 u. 11, Urkunde Nr. 14. making it reasonable to assume that the wall existed in 994, matching the archaeological findings.Wintergerst, S. 95 und 98.
The position of the historic wall is best documented in the north-west, due to numerous excavations the archaeological advantage of being able to dig in undisturbed layers. The fortification ran between the Hainer Hof north of the Kannengiessergasse and a wide gate discovered by Thomas in the area of the Borngasse. From there, it continued to the Steinernes Haus and – contrary to expectations – made a sharp turn towards the Römerberg.
The discovery of an east–west wall at the northern Samstagsberg presupposes the existence of another gate at the position where one leaves the Römerberg today, entering the Alter Markt in the direction of the cathedral.Thomas 1908, S. 171. If a line were drawn from there to the findings in the area of the Saalhof, it leads to the conclusion that the east-west wall must have made a near 90° turn at this point, directly connecting to the stronger wall on the bank of the Main. However, the significant disruption of the soil below the Römerberg, which was noticed by Thomas, makes it equally possible that the previously mentioned east–west wall section was constructed later, and was a direct connection between the north-west wall and the southern part of the wall. Archaeologically, the southern part of the wall has only been confirmed to have existed as far as the Geistpförtchen. Furthermore, the simultaneous existence of the southern wall and the Ottonian wall is disputed.Stamm, S. 16 und 41.
Presumedly, the Dreimetermauer ("three-metre wall", referring to the thickness of the wall at the Main) followed the natural course of the river east of the Geistpförtchen as well. The riverside at the time was at the same height as the southern Saalgasse. The wall is assumed to have then run east of the cathedral, about in the middle of the Kannengießergasse, from north to south, connecting back to the proven position of the wall along today's Braubachstraße.
The surprising archaeological findings of the early twentieth century have been explained by post-war excavations. Exactly in the middle of the wall-enclosed area, the Carolingan palace was located together with its associated farm buildings and the predecessor of the cathedral, the Salvatorkirche, consecrated in 852. Carolingian Frankfurt was thus much smaller than historically expected, and its fortification, according to present knowledge, has been built by the subsequent Ottonian dynasty around 1000.
Staufenmauer wall