Conrad I, Count of Oldenburg
Conrad I of Oldenburg (died 1347) was the Count of Oldenburg from 1344 to 1347.
He succeeded his brother, John III of Oldenburg.
He was the son of John II of Oldenburg and Hedwig of Diepholz.
Conrad married Ingeborg, the daughter of Count Gerhard IV of Holstein-Plön.
They had four children:
Conrad I of Oldenburg is also a male-line ancestor of Queen Margrethe II of Denmark, King Harald V of Norway, and of Philip, Duke of Edinburgh, and thus of Charles, Prince of Wales, and Prince William, Duke of Cambridge.
Anthony I, Count of Oldenburg
Anthony I, Count of Oldenburg and Delmenhorst( 1505 – 22 January 1573, Oldenburg) was a member of the House of Oldenburg and was the Imperial Count of the Counties of Oldenburg and Delmenhorst within the Holy Roman Empire of German Nation.
His parents were John V, Count of Oldenburg( 1460- 1525) and Anna of Anhalt- Zerbst.
Prince Roman Petrovich of Russia
Prince Roman Petrovich of Russia( 17 October 1896 – 23 October 1978) was a member of the House of Romanov.
Christian, Duke of Oldenburg
Christian, Duke of Oldenburg( born 1 February 1955) is the head of the Grand Ducal Family of Oldenburg.
John V, Count of Oldenburg
John V, Count of Oldenburg and Delmenhorst (also counted as John XIV, including also non-ruling namesake siblings; 1460, Oldenburg – 10 February 1526, Oldenburg) was a member of the House of Oldenburg.
He was the ruling Count of Oldenburg from 1500 to 1526.
His parents were Gerhard VI, Count of Oldenburg and Adelheid of Tecklenburg.
Duke Peter of Oldenburg
Duke Constantine Frederick Peter of Oldenburg (26 August 1812 in Yaroslavl, Russian Empire – 14 May 1881 in St. Petersburg, Russian Empire) was a Duke of the House of Oldenburg.
He was the grandfather of Duke Peter of Oldenburg as well as grandfather of Grand Duke Nicholas Nikolaevich, General of the Imperial Russian Army during World War I.
His great-great grandson, Nicholas Romanov, was the President of the Romanov Family Association until his death in 2014.
Peter of Oldenburg was a scholar and philanthropist.
He was also noted composer of music.
In 1857 he composed the music for
Marius Petipa's ballet "La Rose, la Violette et le Papillon".
The "Pas d'Esclave" from the ballet "Le Corsaire", which is taken from his score for this work, is still heard in theatres all over the world.
Countess Alexandra von Zarnekau
Countess Alexandra Constantinovna von Zarnekau (Russian: графиня Александра Константиновна Зарнекау, 10 May 1883 - 28 May 1957) was the eldest daughter of Duke Constantine Petrovich of Oldenburg and his morganatic wife, Agrippina Japaridze, Countess von Zarnekau.
At age 17, on 11 February 1900, Countess Alexandra married Prince George Alexandrovich Yuryevsky, the son of Tsar Alexander II by his mistress (and later wife), Ekaterina Mikhailovna Dolgorukova, the Princess Yourievskya.
They were married at Nice, France, and had one child, Prince Alexander Georgievich Yourievsky, who was born 20 December 1901.
Alexandra and George divorced in 1908.
Countess Alexandra married secondly to Leo Vassilievich Narishkin on 17 October 1908 at Paris, France.
During the First World War, Countess Alexandra worked as an administrator of the Russian hospital at Saloniki.
After the war, she settled in Paris, France.
She died there on 28 May 1957 at age 74.
John VII, Count of Oldenburg
Count John VII of Oldenburg and Delmenhorst( nicknamed" the Dike Builder"; 9 September 1540 in Oldenburg – 12 November 1603 in Oldenburg) was a member of the House of Oldenburg and was the ruling Count of County of Oldenburg from 1573 until his death.
His parents were Count Anthony I of Oldenburg and Sophie of Saxe- Lauenburg.
Duke Constantine Petrovich of Oldenburg
Duke Constantine Frederick Peter of Oldenburg (tr. ; 9 May 1850 - 18 March 1906) was a son of Duke Peter Georgievich of Oldenburg and his wife Princess Therese of Nassau-Weilburg Known in the court of Tsar Nicholas II as Prince Constantine Petrovich Oldenburgsky, he was the father of the Russian Counts and Countesses von Zarnekau.
Duchess Therese Petrovna of Oldenburg
Duchess Therese Wilhelmine Olga Friederike of Oldenburg (30 March 1852 – 19 April 1883) was the youngest daughter of Duke Peter Georgievich of Oldenburg and his wife Princess Therese of Nassau-Weilburg.

Question: Where was the place of death of Duke Constantine Petrovich Of Oldenburg's father?
Answer: St. Petersburg