baron de Charles Henri Gleichen

Born in 1733 and dead in 1807, Baron de Gleichen — also known as Karl Heinrich von Gleichen or Charles-Henri de Gleichen — was a German-born diplomat and man of letters whose life took him across several European courts. French and German sources identify him with the memoir Souvenirs de Charles-Henri Baron de Gleichen, a work published after his lifetime from his recollections.

His career was tied to diplomacy and court life, which gave him access to major personalities and political circles of the late 18th century. That experience is what makes his writing interesting today: rather than a distant history, it reads like someone remembering the rooms, rivalries, and conversations he personally witnessed.

The surviving image most clearly associated with him appears to be a monument rather than a contemporary portrait, so a reliable portrait photograph was not available from the sources I checked. For readers drawn to memoirs, his work stands out for its firsthand glimpse of European society just before and during a time of enormous change.