Sophie of Merenberg
Countess Sophie Nikolaievna of Merenberg, Countess de Torby( 1 June 1868 – 14 September 1927), also known as" Countess Torbay", was the elder daughter of Prince Nikolaus Wilhelm of Nassau and his morganatic wife, Natalia Alexandrovna Pushkina( who had been granted the title of Countess of Merenberg).
Frederick William, Prince of Nassau-Weilburg
Frederick William, Prince of Nassau- Weilburg( 25 October 1768, The Hague – 9 January 1816, Weilburg) was a ruler of Nassau- Weilburg.
In 1806 he was given the title of Prince of Nassau, while his cousin, Prince Frederick Augustus of Nassau- Usingen, became the Duke of Nassau.
Frederick William died in January 1816, only two months before his cousin.
Both men were succeeded by Frederick William's son, William.
Frederick Augustus, Duke of Nassau
Friedrich August, Duke of Nassau, Prince of Nassau- Usingen( 23 April 1738 in Usingen – 24 March 1816 in Wiesbaden) was the last Prince of Nassau- Usingen and, jointly with his cousin, Friedrich Wilhelm of Nassau- Weilburg, first Duke of Nassau.
He died without surviving male issue and was succeeded by his cousin's son, Wilhelm.
Prince Nikolaus Wilhelm of Nassau
Prince Nikolaus Wilhelm of Nassau (20 September 1832 – 17 September 1905), was the only son of William, Duke of Nassau by his second wife Princess Pauline of Württemberg.
Adolf of Nassau (1540–1568)
Adolf of Nassau (Dillenburg, 11 July 1540 – Heiligerlee, 23 May 1568) was a count of Nassau, also known as Adolphus of Nassau.
He was the fourth son and sixth child of William I, Count of Nassau-Dillenburg and Juliana of Stolberg.
He was the second youngest brother of William the Silent.
Princess Pauline of Württemberg (1810–1856)
Princess "Pauline" Friederike Marie of Württemberg, full German name: "Pauline Friederike Marie, Prinzessin von Württemberg" (25 February 1810, Stuttgart, Kingdom of Württemberg – 7 July 1856, Wiesbaden, Duchy of Nassau) was a member of the House of Württemberg and a Princess of Württemberg by birth.
Through her marriage to William, Duke of Nassau, Louise was also a Duchess consort of Nassau.
Pauline is an ancestress of the present Belgian, Danish, Dutch, Luxembourg, Norwegian, and Swedish Royal families.
Walram II, Count of Nassau
Walram II of Nassau,( – 24 January 1276), was Count of Nassau and is the ancestor of the Walramian branch of the House of Nassau.
Henry I, Count of Nassau-Siegen
Henry I of Nassau- Siegen,( – between 13 July and 14 August 1343) was Count of Nassau- Siegen, a part of the County of Nassau, and ancestor of the House of Nassau- Siegen.
He comes from the Ottonian branch of the House of Nassau.
Otto I, Count of Nassau
Otto I of Nassau,( † between 3 May 1289 and 19 March 1290) was Count of Nassau and is the ancestor of the Ottonian branch of the House of Nassau.
Elisabeth of Nassau-Dillenburg, Countess of Wied
Elisabeth of Nassau-Dillenburg (1 December 1488 – 3 June 1559 in Dillenburg) was a member of the House of Nassau.
She was a daughter of John V of Nassau-Dillenburg and his wife Elisabeth of Hesse-Marburg.
Her brothers were Henry III of Nassau-Breda, John of Nassau-Vianden-Dietz, Ernest of Nassau and William the Rich.
Her sister was Maria of Nassau.

Question: Which country Prince Nikolaus Wilhelm Of Nassau's mother is from?
Answer: German