Frederick Augustus II was the last ruling Grand Duke of Oldenburg. He married Princess Elisabeth Anna of Prussia, daughter of Princess Maria Anna of Anhalt-Dessau and Prince Frederick Charles of Prussia. After her death, he married Elisabeth Alexandrine of Mecklenburg-Schwerin.

Oldenburg (German pronunciation: [ˈɔldn̩bʊʁk] ; Northern Low Saxon: Ollnborg) is an independent city in the state of Lower Saxony, Germany. The city is officially named Oldenburg (Oldb) (Oldenburg in Oldenburg) to distinguish from Oldenburg in Holstein.