René-Eustache, marquis d'Osmond

His uncle, Barnabé, comte d'Osmond (1716-1792), was Chamberlain of the Royal Orleans household and introduced him to the court of Louis Philippe I, Duke of Orléans (1725-1785).

René-Eustache d'Osmond then became in regular attendance at the Castle of St Assisi, where the Royal Duke had taken up residence with his morganatic wife, Charlotte marquise de Montesson.

They had two children: In 1786 d'Osmond secured the purchase of the Armand-Joseph, duc de Charost's coal mining interests at Firminy and Roche-la-Molière, near Saint-Étienne, but his perceived business coup ran into difficulties from the outset since their smooth operation was hampered by local hostility.

His brother, Antoine-Eustache d'Osmond (Constitutional Bishop of Nancy), who had sided with the Emperor Napoleon, ensured that his name was removed from the list of emigrants enabling him to return to France during the régime of the First French Empire.

He was created a marquis and peer of France by Royal decree, dated 31 August 1817 (in the title previously held by a senior branch of the d'Osmond family, extinct 1771).