History:

• The church probably stood in place of a pagan place of worship initially in the course of Christianisation as a Michael chapel.
• In the 11th century/after 1081, Bishop Benno II's plan to build a Benedictine monastery failed. This led to the renewed foundation of a monastery by Bishop Udo of Steinfurt (1137-41). In the process, Benno's already existing church was taken over.
• In the late Middle Ages, there were hardly any frequent disputes with the citizens of Osnabrück due to the monastery's commercial activity with subsequent devastations. Also because of its strategically favourable location above the city with various sieges, lootings and fires, including during the 30s war.
• Then it came to the dissolution of the monastery during the secularisation in 1803. After that, the facility was used as an armoury and military hospital.
• In the 1860s, a sanatorium and nursing home was built on the former monastery grounds. In 1954, the state hospital was built, since ... AMEOS clinic. Since then, the monastery church has served as a simultaneous church.

Stories / Legends:

• Figure of St. Gertrude:
• Provides protection against rats and mice. Due to the  hand position here rather protector of mice (Pastor Heyl).
• "Gertrudenberger Loch":
• A dowser (when?) claimed that there were underground passages under the city which would also lead to the cathedral or the bishop. In Osnabrück, the rumour persists that the Gertrudenberg nuns would have reached the bishop directly through this.
• Fact: In the past, nuns probably suddenly appeared in the city, but they were not seen coming. From the preserved monastery cellar, there is a former access to the cave system in the Gertrudenberg. In case of siege or danger (the Hasetor railway station did not yet exist), the nuns had the possibility to reach the Herrenteichswall unseen by this route, then to enter the city through this and the passage in the Hohe Brücke and apparently "suddenly" appeared there.
• Convent brewery (instead of the abbesses' house) / Gertrudenminne:
• The nuns handed out the home-brewed Gertruden beer to travellers. Women who stopped at the Gertruden monastery on the way back from a pilgrimage to St. Annen (Schiplage) got "beergeid" or "to verdrinken" (in: Guide St. Anna Schiplage)
• "Die heilige Feme": M. Rickling, Kirche - Kriege - Goldene Schätz, ..., p. 118
• The famous writer and native of Osnabrück, Erich Maria Remarque, was organist in the hospital church in 1921/22 ("Der schwarze Obelisk", 1956).