of
Hesse-Darmstadt (1769). Louis was born on 14 June 1753 as the third child and eldest son of the later Landgrave
Louis IX of Hessen-Darmstadt, and his spouse
Countess Palatine Caroline of Zweibrücken, a daughter of
Christian III, Count Palatine of Zweibrücken. He was born in the town of
Prenzlau in
Brandenburg, where his father, who was in
Prussian military service, was stationed. The children grew up with the mother in the town of
Buchsweiler, which had previously been the residence of the Counts of
Hanau-Lichtenberg, while the father stayed mainly in the town of
Pirmasens to attend his military career. In 1766, when Louis was 13, his mother's court moved from Buchsweiler to Darmstadt. At the death of his grandfather on 17 October 1768, his father succeeded as landgrave, and Louis himself became heir to the landgraviate with the title of
hereditary prince. Ludwig studied at the
University of Leiden from
1769 and subsequently undertook his
Grand Tour to
London and
Paris. In
France he met, among others, the French
philosophers
Jean le Rond d'Alembert and
Denis Diderot, who were some of the prominent figures of the
Age of Enlightenment, and
editors of the first modern
encyclopedia. In
1773 he traveled with the German-born French
writer and
critic Friedrich Melchior Grimm to the court of Frederik the Great in
Prussia, where his sister
Frederica Louisa was married to the
heir presumptive Frederick William. Finally, he traveled on to
Russia, where in
1773 he attended the wedding of his second sister
Wilhelmina Louisa in
St. Petersburg to the heir to the Russian throne,
Grand Duke Paul. As a Russian general Ludwig fought in
1774 in the
Russo-Turkish War, and the same year he became
freemason in the
lodge "To the crowned flag "in
Moscow. == Marriage ==