A church at the site of Sant'Agata was present by the 8th century, when the neighborhood was located outside the city walls, but after the 1184 fire destroyed the ancient church, it was reconstructed in the 15th-century in Gothic style. Destruction by fire of this church was somewhat paradoxical, since Saint Agatha was the saint invoked for protection against fires. Further modifications were completed along the centuries, leading to a pastiche of styles. The incomplete 14th-century facade has a Renaissance architecture facade, decorated with Baroque statuary.
Inside, the presbytery dates from the 15th century, the ceiling from the 16th century, the altars and fresco decoration from the 1680s, and the chapel of the Santissimo Sacramento is from the 18th century. The main altarpiece depicting Sant'Agata with Saints Peter, Paul, Lucia, Apollonia standing before the cross (1522) is a masterwork by Francesco Prata from Caravaggio.
References:The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.