Born in
Baden-Baden, Louis II was the only child of
Albert I, Prince of Monaco (1848–1922), and
Lady Mary Victoria Douglas-Hamilton (1850–1922). His mother was a daughter of
William Hamilton, 11th Duke of Hamilton and
Princess Marie Amelie of Baden. Louis was born within a year of his parents' marriage, but his mother, a strong-willed 19-year-old, disliked Monaco and was unhappy with her husband. She left the country permanently shortly after the birth, and the couple's marriage was annulled in 1880. Louis was raised in Germany by his mother and stepfather, Count (later Prince)
Tassilo Festetics von Tolna, along with his eldest half-sister Maria-Mathilde (later grandmother of
Princess Ira von Fürstenberg); he did not see his father until age 11 when he was obliged to return to Monaco to be trained for his future princely duties. Louis's father,
Prince Albert I, was a dominating personality who had made Monaco a centre of cultural activity and whose intellectual achievements were recognized around the world. Unhappy to be living with his cold and distant father, Louis went to France as soon as he was old enough to enroll in
Saint-Cyr, the French national military college. Four years later, after graduating, he was attached to the
French Foreign Legion and then served with a regiment of
Chasseurs d'Afrique (African Light Horse) in
Algeria. Before being stationed in
Algeria, he met
Marie Juliette Louvet (1867–1930), a
cabaret singer, on a short official visit to Paris. They had an out-of-wedlock daughter,
Charlotte Louise Juliette, born on 30 September 1898 in
Constantine, Algeria. There is no mention of Louvet in the authorized biography of her grandson,
Prince Rainier III, who is Monegasque by nationality but whose ancestors include people of
French,
Mexican,
Italian,
German,
Scottish, and
English nationality. Louis served in the French Army for four years from 1895 to 1899, reaching the rank of lieutenant. He was awarded the
médaille coloniale (Colonial Medal) and the Cross of the
Legion of Honor. At the conclusion of his military service, he returned to Monaco, leaving behind his mistress and daughter. At the outbreak of
World War I, he re-enlisted in the
French Army as a volunteer, serving as a staff officer under General
Franchet d’Espèrey. Louis was made a Grand Officer of the Legion of Honor and eventually became a
brigadier general. ==Solution to succession aspects in 1911–18==