|Died||9 November 1817
|Title||Comte de Mosloy|
Becoming a student of Christophe-Guillaume Koch and a friend of Emmanuel-Joseph Sieyès, he left France in 1779 on an embassy to the new United States of America as private secretary to the chevalier de La Luzerne. While in the United States, he succeeded François Barbé-Marbois as secretary of the legation in May 1785, then served as chargé d'affaires ad interim twice. George Washington and the main members of Congress honoured him with their friendship. He married Elizabeth Livingston, in March 1787, but she died in December.
He returned to France at the end of 1792, and shortly afterwards the Committee of Public Safety made him head of the first political division for foreign affairs. However, the fall of the Girondins on 31st May 1793 led to Otto's dismissal and arrest. He then came close to being guillotined, but survived and followed Emmanuel-Joseph Sieyès to Berlin as secretary to the legation, then stayed there as chargé d'affaires when Sieyès was elected Director. A letter written by him on 6 July 1799 seems to be the earliest recorded use of the term Industrial Revolution; as he announces in the letter that that revolution began in France. He was moved to London in 1800, at first as commissioner for the exchange of prisoners of war, then as minister plenipotentiary. Commanded to look into negotiations with the British cabinet, in 1801 he negotiated the preliminaries of the peace of Amiens.
In 1803, he was posted to the court of the Maximilian, Prince-Elector of Bavaria in Munich. In 1805, his influence on the Elector impressed Napoleon I, who appointed him to the Conseil d'État and made him a Grand Officer of the Légion d'honneur. In 1810 he was made ambassador to Vienna, where he negotiated the conditions for Napoleon's second marriage to archduchess Marie Louise. Napoleon thanked him by making him count of Mosloy (comte de Mosloy) later in 1810. During his stay in Vienna, Louis-Guillaume Otto came into contact with the chancellor of the Austrian Empire, count Metternich, who was another former student of Koch.
He was kept out of politics during the First Restoration and retired after the Second Restoration, since he had served as under-secretary for foreign affairs from 24 March to 22 June during the Hundred Days. On his death in 1817 he was buried in the 37th division of the Cimetière du Père-Lachaise.
Coat of arms
"Écartelé, aux 1 et 4 fascé d'or et de sable ; au 2 d'argent à une loutre de sable issante d'une rivière d'azur engoulant un poisson d'or; au 3 de gueules au lion léopardé d'or tenant un coeur d'argent"
- Julia Post Mitchell, Julia Post Mitchell Kunkle (1916). St. Jean de Crèvecoeur. Columbia University Press.
- Crouzet, François (1996). "France". In Teich, Mikuláš; Porter, Roy. The industrial revolution in national context: Europe and the USA. Cambridge University Press. p. 45. ISBN 978-0-521-40940-7. LCCN 95025377.