Louis V, Landgrave of Hesse-Darmstadt
Louis V of Hesse-Darmstadt (24 September 1577 – 27 July 1626) was the Landgrave of Hesse-Darmstadt from 1596 to 1626.
He was born on 24 September 1577 as the son of George I, Landgrave of Hesse-Darmstadt and Magdalene of Lippe.
In 1604 he inherited a part of Hessen-Marburg after the death of Louis IV of Hesse-Marburg who was childless.
The other half went to Maurice of Hesse-Kassel (or Hesse-Cassel), but since Maurice was a Calvinist, Ludwig claimed a right on the whole of Hesse-Marburg.
Lutheran professors of the University of Marburg who refused to convert to Calvinism founded in 1607 the University of Gießen which was named "Ludoviciana".
This led to a conflict during the Thirty Years' War, between Louis V, who stood on the side of the Emperor, and Maurice, who was on the side of the Protestants.
Hesse-Darmstadt suffered severely from the ravages from the Swedes during the conflict.
The Landgrave died in 1626 and he was succeeded by George II, Landgrave of Hesse-Darmstadt.
In 1722, Johann Georg Liebknecht, an astronomer at the University of Gießen, named a star, which he thought was a planet, Sidus Ludoviciana after Ludwig V.
Natalia Alexeievna (Wilhelmina Louisa of Hesse-Darmstadt)
Natalia Alexeievna, Tsarevna of Russia( 25 June 1755 – 26 April 1776), was the first wife of Paul Petrovich, Tsarevich of Russia( future Emperor Paul I), son of the Empress Catherine II.
She was born as Princess Wilhelmina Louisa of Hesse- Darmstadt as the fifth child of Louis IX, Landgrave of Hesse- Darmstadt and his spouse Countess Palatine Caroline of Zweibrücken.
Louis VI, Landgrave of Hesse-Darmstadt
Louis VI of Hesse-Darmstadt  (25 January 1630 – 24 April 1678) was Landgrave of Hesse-Darmstadt from 1661 to 1678.
He was the eldest of three sons of the Landgrave George II of Hesse-Darmstadt and Sophia Eleonore of Saxony.
Landgravine Auguste of Hesse-Homburg
Landgravine" Auguste" Fredericka of Hesse- Homburg( full German name:" Auguste Friederike, Landgräfin von Hessen- Homburg"; 28 November 1776, Bad Homburg vor der Höhe, Landgraviate of Hesse- Homburg, Holy Roman Empire – 1 April 1871, Ludwigslust, Grand Duchy of Mecklenburg- Schwerin), was a member of the House of Hesse and a Landgravine of Hesse- Homburg by birth.
Through her marriage she was also a member of the House of Mecklenburg and Hereditary Grand Duchess of Mecklenburg- Schwerin.
She was the sixth child and fourth daughter of Frederick V, Landgrave of Hesse- Homburg and his wife Landgravine Caroline of Hesse- Darmstadt, in turn daughter of Louis IX, Landgrave of Hesse- Darmstadt.
Princess Amalie of Hesse-Darmstadt
Princess Amalie of Hesse- Darmstadt( 20 June 1754 – 21 June 1832) was a Hereditary Princess of Baden by marriage to Charles Louis, Hereditary Prince of Baden.
She was the daughter of Ludwig IX, Landgrave of Hesse- Darmstadt and Henriette Karoline of Palatine- Zweibrücken.
Louis IX, Landgrave of Hesse-Darmstadt
Louis IX of Hesse-Darmstadt  (15 December 1719 – 6 April 1790) was the Landgrave of Hesse-Darmstadt from 1768 - 1790.
He was a son of Louis VIII, Landgrave of Hesse-Darmstadt, and Charlotte of Hanau-Lichtenberg and Müntzenberg.
He was born in Darmstadt on 15 December 1719.
On 12 August 1741, Louis married Caroline of Zweibrücken, daughter of Christian III, Duke of Zweibrücken.
They had three sons and five daughters, including:
In 1775, Louis married Marie Adelaide of Cheirouze, countess of Lemberg.
On 6 April 1790 Louis died in Pirmasens.
Countess Palatine Caroline of Zweibrücken
Caroline of the Palatinate-Zweibrücken (Henriette Caroline Christiane Louise; 9 March 1721 – 30 March 1774) was Landgravine of Hesse-Darmstadt by marriage to Louis IX, Landgrave of Hesse-Darmstadt.
She was famed as one of the most learned women of her time and known as The Great Landgräfin.
Princess Louise of Hesse-Darmstadt (1757–1830)
Princess and Landgravine Louise of Hesse- Darmstadt( 30 January
1757 – 14 February 1830) was a German princess.
She was the daughter of Louis IX, Landgrave of Hesse- Darmstadt.
On 3 October 1775 she married duke( later grand- duke) Charles Augustus of Saxe- Weimar- Eisenach and as such a member of the court sphere of Weimar Classicism.
She was held to be serious and introverted but also compassionate and sympathetic, in the aftermath of the Battle of Jena which guaranteed her part in the later" myth of WeimarWeimarmythos").
Louis VIII, Landgrave of Hesse-Darmstadt
Louis VIII (German: "Ludwig") (5 April 1691 – 17 October 1768) was the Landgrave of Hesse-Darmstadt from 1739 to 1768.
He was the son of Ernest Louis, Landgrave of Hesse-Darmstadt and Margravine Dorothea Charlotte of Brandenburg-Ansbach.
Princess Caroline of Hesse-Darmstadt
Caroline of Hesse-Darmstadt (2 March 1746, Buchsweiler – 18 September 1821, Homburg) was Landgravine consort of Hesse-Homburg by marriage to Frederick V, Landgrave of Hesse-Homburg.
She was the eldest daughter of Louis IX, Landgrave of Hesse-Darmstadt and his wife Caroline.
She married Frederick V, Landgrave of Hesse-Homburg on 27 September 1768.
The marriage was contracted for diplomatic and political reasons as the symbol of an inheritance dispute between their respective families.
Caroline and Frederick V produced many children but their marriage never developed into a personal relationship, and they lived mostly separated lives.
Caroline often spent time in the famed little villa that was given to her use in the forest near Homburg.

Question: What nationality is Louis Ix, Landgrave Of Hesse-Darmstadt's father?
Answer: German