skos:altLabel | - Grand Duke of Oldenburg
- Oldenburg
- Grand Duchy
- grand duchy
- Duchy of Oldenburg
- Grand Ducal Oldenburg
- Grand Duchy and later Free State of Oldenburg
- Grand Duchy of Oldenburg
- Grand ducal line
- Großherzogtum Olenburg
- Holstein-Gottorp
- Holstein-Oldenburg
- Oldenburg (Grand Duchy)
- Oldenburgish
- Principality of Oldenburg
- State of Oldenburg
- a Grand Duchy of the same name
- duchy of Oldenburg
- grand duchy of Oldenburg
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