Extremely rare certificate of promotion to rank signed by Charles III of Bourbon Duchy of Parma

Interesting and uncommon certificate of promotion of rank of a soldier of the Duchy of Parma Piacenza 
and Guastalla.

The rarity of the document in question is that it is signed in original by the Duke of Parma Charles III, 
then killed in 1854.

Usually these certificates of conferral of rank were signed in the name and on behalf of the Duke 
by high officials or members of the government, finding them with the original Duke's signature 
is extremely rare.

Excellent state of conservation