The church of the monastery is one of the most important sacred buildings in Salzgitter. The history of this place of worship and that of its two predecessor buildings goes back to the time when the Damenstift was founded.
St. Nicholas' Castle Chapel initially served as the collegiate church until the first church was completed in 1070 and could be consecrated by Merseburg Bishop Werner. It had to be demolished around 1160 due to dilapidation and replaced by a new building.
The construction of the new Romanesque church began in 1165 under Provost Gerhard II. On the night of January 21-22, 1328, a fire destroyed a large part of the church, with only the choir, northern transept and side aisle being spared.
After it was rebuilt, the church building was mainly affected by military conflicts, but it was not until the Thirty Years' War that it was destroyed to such an extent that a new building became unavoidable.
Between 1751 and 1758, Duke Karl I (1735 to 1780) had the present Baroque church built by the architect and officer Anton Ulrich von Blum and, after his death, by Friedrich Grützmann.
The interior of the church is divided by Corinthian wooden pillars into an elongated central nave with semi-circular ends and a two-storey ambulatory, which is extended in the middle of the nave by risalits.
The pulpit altar was installed in 1756. Later, a wall was erected in the axis of the second, now blinded window from the west, separating a narrow room from the church. This room, together with the tower and an adjoining half-timbered building, served as a dwelling for a lady of the monastery.
The abbess's residence in the south of the complex, built in 1691, is connected to the convent buildings and the church by a barrel-vaulted corridor.
In 1938, Wohnungs AG of the former Reichswerke (now Salzgitter AG) built 24 large apartments in the abbey buildings. Further extensive modernization work was carried out in the 1960s
(Source: Cultural monuments in the town of Salzgitter, published by Braunschweigische Landschaft e. V., www.braunschweigischelandschaft.de, 2001)