Charles Christian, Prince of Nassau-Weilburg
Charles Christian, Prince of Nassau-Weilburg (Weilburg, 16 January 1735 – Münster-Dreissen, near Kirchheim, 28 November 1788), till 1753 Count of Nassau-Weilburg, was the first ruler of the Principality of Nassau-Weilburg between 1753 and 1788.
Archduke Charles, Duke of Teschen
Archduke Charles Louis John Joseph Laurentius of Austria, Duke of Teschen (5 September 177130 April 1847) was an Austrian field-marshal, the third son of Emperor Leopold II and his wife, Maria Luisa of Spain.
He was also the younger brother of Francis II, Holy Roman Emperor.
Despite being epileptic, Charles achieved respect both as a commander and as a reformer of the Austrian army.
He was considered one of Napoleon's more formidable opponents.
He began his career fighting the revolutionary armies of France.
Early in the wars of the First Coalition, he saw victory at Neerwinden in 1793, before being defeated at Wattignies 1793 and Fleurus 1794.
In 1796, as chief of all Austrian forces on the Rhine, Charles defeated Jean-Baptiste Jourdan at Amberg and Würzburg, and then won a victory at Emmendingen that forced Jean Victor Marie Moreau to withdraw across the Rhine.
He also defeated opponents at Zürich, Ostrach, Stockach, and Messkirch in 1799.
He reformed Austria's armies to adopt the nation-at-arms principle.
In 1809, he entered the War of the Fifth Coalition and inflicted Napoleon's first major setback at Aspern-Essling, before suffering a defeat at the bloody Battle of Wagram.
After Wagram, Charles saw no more significant action in the Napoleonic Wars.
As a military strategist, Charles was able to successfully execute complex and risky maneuvers of troops.
However, his contemporary Carl von Clausewitz criticized his rigidity and adherence to "geographic" strategy.
Austrians nevertheless remember Charles as a hero of the French Revolutionary and Napoleonic wars.
Ernest Casimir, Count of Nassau-Weilburg
Ernest Casimir of Nassau- Weilburg( 15 November 1607 – 16 April 1655) was the founder of the" younger" line of Nassau- Weilburg.
He was a son of Louis II, Count of Nassau- Weilburg and his wife Anna Maria of Hesse- Kassel( 1567 – 1626).
Maria Theresa of Austria (1816–1867)
Maria Theresa of Austria (Maria Theresia Isabella; 31 July 1816 – 8 August 1867) was the second wife of Ferdinand II of the Two Sicilies.
She was the eldest daughter of Archduke Charles, Duke of Teschen and Princess Henrietta of Nassau-Weilburg.
Her paternal grandparents were Leopold II, Holy Roman Emperor and Maria Luisa of Spain.
Her maternal grandparents were Frederick William of Nassau-Weilburg (1768–1816) and his wife Burgravine Louise Isabelle of Kirchberg.
Maria Theresa was Princess-Abbess of the Theresian Royal and Imperial Ladies Chapter of the Castle of Prague (1834-1835).
Louis I, Count of Nassau-Weilburg
Count Louis I of Nassau- Weilburg( 1473 – 28 May 1523) was a son of Count John III of Nassau- Weilburg and his wife, Elisabeth of Hesse.
In 1492, Louis I succeeded his grandfather Philip II as Count of Nassau- Weilburg, because his father had already died in 1480.
In 1502, Louis I married Margaret( 1487- 1548), a daughter of Adolf III of Nassau- Wiesbaden- Idstein.
Louis and Margaret had the following children:
Princess Therese of Nassau-Weilburg
Princess Therese Wilhelmine Friederike Isabelle Charlotte of Nassau- Weilburg,( Terezya Vasilyevna Nassauskaya; 17 April 1815 in Weilburg, Duchy of Nassau – 8 December 1871 in Prague, Kingdom of Bohemia, Austria – Hungary) was a member of the House of Nassau- Weilburg and a Princess of Nassau- Weilburg by birth.
Through her marriage to Duke Peter of Oldenburg, Therese was also a Duchess of Oldenburg.
Philip IV, Count of Nassau-Weilburg
Philip IV of Nassau- Weilburg, also known as Philip III of Nassau- Saarbrücken( 14 October 1542 in Weilburg – 12 March 1602 in Saarbrücken) was Count of Nassau- Weilburg from 1559 until his death and since 1574 also Count of Nassau- Saarbrücken.
Both possessions belonged to the Walram line of the House of Nassau.
In Weilburg, he was the fourth count named Philip, but only the third in Saarbrücken, because his father, Philip III of Nassau- Weilburg never held Nassau- Saarbrücken.
John III, Count of Nassau-Weilburg
John III of Nassau- Weilburg( 27 June 1441 – 15 July 1480) was count of Nassau- Weilburg as co-regent with his father.
He came from the Walramian branch of the House of Nassau.
Princess Henrietta of Nassau-Weilburg
Henrietta Alexandrine Friederike Wilhelmine of Nassau-Weilburg, then of Nassau
(areas now part of Germany) (30 October 1797 Palace Ermitage, Bayreuth – 29 December 1829, Vienna) was the wife of Archduke Charles, Duke of Teschen.
Her husband was a notable general of the Napoleonic Wars and victor of the Battle of Aspern-Essling against Napoleon I of France.
Louis II, Count of Nassau-Weilburg
Louis II of Nassau- Weilburg( 9 August 1565, Weilburg – 8 November 1627, Saarbrücken) was a count of Nassau- Weilburg.

Question: Who is the mother-in-law of Princess Henrietta Of Nassau-Weilburg?
Answer: Maria Luisa of Spain