The Oldenburg Mausoleum at the Gertrudenfriedhof was constructed from 1785 upon the death in childbirth of 20-year-old Frederica of Württemberg, the wife of the future Peter I, Grand Duke of Oldenburg. She was the first to be buried there upon completion in 1790. The mausoleum was built on the edge of the cemetery grounds and towers over it.
Burials of the Oldenburg rulers continued over the following years and the following women are buried there:
1. Adelheid of Anhalt-Bernburg-Schaumburg-Hoym
2. Ida of Anhalt-Bernburg-Schaumburg-Hoym
3. Cecilie of Sweden
4. Amalia of Sweden
5. Elisabeth Anna of Prussia
6. Elisabeth of Saxe-Altenburg
7. Rixa of Oldenburg
8. Elisabeth Alexandrine of Mecklenburg-Schwerin
9. Donata of Castell-Rüdenhausen
10. Ameli of Löwenstein-Wertheim-Freudenberg
11. Frederica of Württemberg
The mausoleum is generally not open to the public but the public was given a look inside after renovations in 2013.