Historical summary

742 First written mention of Erfurt
1060 The collegiate church is converted into a Benedictine abbey under Archbishop Siegfried I.
1080 Erfurt is conquered by Heinrich IV and the abbey is destroyed by fire

1103 – 1147

The new abbey and church of St Peter and St Paul is constructed in the Hirsau style
1168 The town’s fortifications are extended to include Petersberg hill
1181 Henry the Lion submits to Emperor Frederick Barbarossa at the Imperial Diet in St Peter’s Church

The Archbishop of Mainz orders the construction of the citadel after he subjugates the city of Erfurt.

The first construction phase in the new Italian style is shaped by Antonio Petrini, architect to the court of the Elector of Mainz.

1707 – 1726

Further construction under the stewardship of Maximilian von Welsch, a military architect from Mainz (second period of construction)
1802 The citadel receives a Prussian garrison
1803 St Peter’s Abbey is secularised and the church inventory is sold off

1806 – 1813

The citadel falls to the French army. During a visit, Napoleon orders that the fortifications be strengthened. The French garrison comes under fire, and St Peter’s Abbey and several of the citadel’s other buildings are destroyed
1814 The citadel once again falls into Prussian hands

1815 – 1866

Extension of the citadel based on a new Prussian fortification system (third period of construction)
1820 The remnants of the Romanesque basilica are covered with a tall roof and used to store flour and weapons
1873 Kaiser Wilhelm I orders the citadel’s fortifications to be removed, but only some are
until 1963 Military use
from 1965 Petersberg Citadel is repurposed
since 1990 This important example of fortification architecture is restored, refurbished and opened up to visitors and local residents