Petershausen Abbey was founded as an exempt abbey named after Saint Peter in 983 by Bishop Gebhard of Constance, located on the northern shore of the Rhine river opposite to the episcopal residence at Constance with its cathedral. Gebhard dedicated the monastery church to Pope Gregory the Great and settled the abbey with monks descending from Einsiedeln.
Under Bishop Gebhard III of Zähringen and Abbot Theodoric (1086–1116), the Hirsau Reforms were introduced. In 1097 a filial monastery was established at Mehrerau near Bregenz. As Petershausen sided with the papacy in the Investiture Controversy, Gebhard III in 1103 was deposed at the instigation of Emperor Henry IV. The abbey was closed until 1106, the monks fled to the newly established Kastl Abbey in Bavaria. In 1159 the monastery burnt down, and was rebuilt and extended between 1162 and 1180. Facing the claims of Swabian nobles like the Counts of Montfort, the abbots became supporters of the Imperial Hohenstaufen dynasty. Under Emperor Frederick II (1220–50), Petershausen became reichsfrei, gaining territorial independence.
During the Council of Constance (1414–18), the German king Sigismund of Luxembourg stayed at the abbey and the Petershausen abbot even gained the pontifical vestments from Antipope John XXIII. Nevertheless the monastery declined during the 14th and 15th centuries, pressed hard by Konstanz claiming the status of an Imperial city, as well as by the diocese. The attempts of Prince-Bishop Hugo von Hohenlandenberg to incorporate Petershausen were blocked by Emperor Maximilian I of Habsburg. The abbey was charged by the Konstanz citizens during the Protestant Reformation and the brothers were expelled. It was again ravaged by Imperial troops during the Schmalkaldic War, after which the City of Konstanz in 1548 was incorporated into the Habsburg possessions of Further Austria. The monks did not return until 1556.
Petershausen was finally secularised to Baden in 1802; the library was bought by the University Library Heidelberg. Margrave Charles Frederick of Baden had parts of the abbey rebuilt as a private residence for his sons. The St Gregory Church was demolished in 1832. The remaining premises were later used as a psychiatric hospital and as barracks. They now accommodate a number of administrative and educational functions and the Archaeological Museum of Baden-Württemberg.References:
Roman Walls of Lugo are an exceptional architectural, archaeological and constructive legacy of Roman engineering, dating from the 3rd and 4th centuries AD. The Walls are built of internal and external stone facings of slate with some granite, with a core filling of a conglomerate of slate slabs and worked stone pieces from Roman buildings, interlocked with lime mortar.
Their total length of 2117 m in the shape of an oblong rectangle occupies an area of 1.68 ha. Their height varies between 8 and 10 m, with a width of 4.2 m, reaching 7 m in some specific points. The walls still contain 85 external towers, 10 gates (five of which are original and five that were opened in modern times), four staircases and two ramps providing access to the walkway along the top of the walls, one of which is internal and the other external. Each tower contained access stairs leading from the intervallum to the wall walk of town wall, of which a total of 21 have been discovered to date.
The defences of Lugo are the most complete and best preserved example of Roman military architecture in the Western Roman Empire.
Despite the renovation work carried out, the walls conserve their original layout and the construction features associated with their defensive purpose, with walls, battlements, towers, fortifications, both modern and original gates and stairways, and a moat.
Since they were built, the walls have defined the layout and growth of the city, which was declared a Historical-Artistic Ensemble in 1973, forming a part of it and becoming an emblematic structure that can be freely accessed to walk along. The local inhabitants and visitors alike have used them as an area for enjoyment and as a part of urban life for centuries.
The fortifications were added to UNESCO"s World Heritage List in late 2000 and are a popular tourist attraction.