If we believe the inscription, this is the oldest Montmorency blade I know of.
On one side it says
NADIE SE META CONMIGO - AŅO DE 1700
QUE MATARE A QUEIN ME ENFADE
QUEIN spell mistake instead for QUIEN
Meaning
NO ONE MESS WITH ME - YEAR OF 1700
I WILL KILL WHOEVER MAKES ME ANGRY
Stilistically I believe the inscription looks rather 1770. I cannot give an opinion about the basket, looking English to me.
On the other hand, Spain used a lot of these blades. Often in America. Sometimes they have silver parts in the grip-pommel. In the Halbach (Solingen) advertisement of 1775 there is a Montmorency with inscriptions to Carlos III (check Halbach in the search). Sometimes they are shortened for infantry.
George Washington had a Montmorency too.
https://www.youtube.com/watch?v=PiClfS5MfI0