Helena Martini
Helena Martini
( 5 July 1728 Bockenheim bei Frankfurt am Main- 8 July 1803 Darmstadt), was the mistress of Louis VIII, Landgrave of Hesse- Darmstadt, from 1744 until 1768.
She was the daughter of Carl Ludwig Martini( d. 1698), an officer, and Susanna Catharina Meser.
In 1744 her father, seeking a promotion, is alleged to have sent Helena to submit his petition to Louis VIII at" Jagdschloss" Kranichstein.
When Louis VIII met her, he kept her as his mistress and did not let her return.
Martini, who became known as" mamsell Lene", enjoyed the unlimited confidence of Louis VIII, was given a house in Darmstadt and accompanied him on his travels.
She supported him in his political conflicts with the branches of the Hesse family, and brought the children of her sister to be raised in her care.
She reportedly had a good relationship with the family of Louis VIII.
Upon his death in 1768, she left the court with a fortune, which she later left to the children of her sister.
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.
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.
Charles I, Landgrave of Hesse-Philippsthal
Charles I, Landgrave of Hesse- Philippsthal( 23 September 1682 – 8 May 1770) was a member of the House of Hesse and Landgrave of Hesse- Philippsthal from 1721 until his death.
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.
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.
Ernest Louis, Landgrave of Hesse-Darmstadt
Ernest Louis of Hesse-Darmstadt  (15 December 1667 – 12 September 1739) was Landgrave of Hesse-Darmstadt from 1678 to 1739.
His parents were Landgrave Louis VI of Hesse-Darmstadt and Elisabeth Dorothea of Saxe-Gotha-Altenburg (1640–1709).
Ernest Louis's desire to emulate the French court under Louis XIV ran his country into debt.
Among those patronized in this cultural milieu were the Baroque composer Christoph Graupner and the gambist Ernst Christian Hesse; also bringing into his service architect Louis Remy de la Fosse for his extensive building program.
Upon his death in 1739, his country's debt was 4 million "gulden", ten times the annual revenue.
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.
Prince Charles William of Hesse-Darmstadt
Karl Wilhelm of Hesse- Darmstadt( 17 June 1693, Nidda- 17 May 1707, Gießen) was a Prince of Hesse- Darmstadt.
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.

Question: What is the date of death of Louis Viii, Landgrave Of Hesse-Darmstadt's father?
Answer: 12 September 1739