Duke Peter of Oldenburg (1926-2016) (1926–2016) Parents Princess Helene of Waldeck and Pyrmont Duke Nikolaus, Hereditary Grand Duke of Oldenburg Children Nikolaus von Holstein-Gottorp, Herzog von Oldenburg Margarete von Holstein-Gottorp, Herzogin von Oldenburg Duke Friedrich August of Oldenburg Georg-Moritz von Holstein-Gottorp, Herzog von Oldenburg Siblings Duchess Eilika of Oldenburg Duchess Altburg of Oldenburg Anton-Günther, Duke of Oldenburg Duke Egilmar of Oldenburg Huno Herzog von Oldenburg Duke Friedrich August of Oldenburg Duchess Rixa of Oldenburg Duke Johann of Oldenburg Partners Gertrud Prinzessin zu Löwenstein-Wertheim-Freudenberg