Prince of Arche and Charleville

Prince of Arche and Charleville is a French title, that was incorporated by marriage to the Duke of Ursel.

Originally, the title was first given upon the Princes of Gonzage, afterwards taken by the French Crown. The 8th Duke Henri used his name of Henri d'Arches as a pseudonym. Although the current duke is currently styled as Prince of Arches, this French title is not recognised by the Kingdom of Belgium. The other titles of the Duke (Count of Grobbendonk and Duke of Hoboken) are legally confirmed.

After the death of her aunt in 1723 Eleanore Christina zu Salm inhereted the principaute.

...
Wikipedia