I distinctly remember this beauty Fernando! It seems that the general consensus was that it was indeed Spanish Colonial and likely for an officer of cavalry or dragoons in the 18th century. I believe another reference was made to the scalloped guard being associated with Spanish colonial swords. The blade is of course German, as was typically the case in that period and into the 19th c.
What is puzzling, as you note, is the curious BB marking on the blade. I am hoping that perhaps some of the members also keen on the swords of Mexico and Spain might associate those initials with something such as regimental or symbolic.
I'm glad you reposted this one here Fernando, and I'm hoping that we might have some luck in getting a bit further on identification.
As always.....more research !!!
All the best,
Jim