Count of Soissons
The Count of Soissons (French: comte de Soissons) was a member of the French court when the country was still a monarchy. They held the rank of Prince of the blood and as a result entitled to the style of Serene Highness but this was used in writing only.  The Counts were the owners of the one time famous Hôtel de Soissons in Paris. The title is unique in the sense that it was later inherited by a woman which was actually forbidden in France at the time.