Tessake, Dussage, Sinclair Saber for comment

[Jim McDougall]

Originally Posted by awdaniec666

In my opinion the correct description would be "Central European Pallasch, 1st half of 17th century, probably Styrian-made".
Certainly not a Dussack, Dussege, Säbel auf teutsch gefasst or any of that Adorable piece.

Exactly!!! You can see how the blade makes a difference. A pallasche is yet another European term for a full length heavy straight blade sword.
In Europe however, while the pallasche was a heavy, straight hacking and chopping sword, often a rider wore a saber at his side, and had a straight thrusting sword termed 'tuck' (estoc) under his leg saddle mounted.
In the Rembrandt painting it is hard to determine if this sword under the right leg is a tuck or pallasche, but the intent is to show the manner these were carried.

[Radboud]

playing the devils advocate here, but that blade looks very similar to the Sudanese kaskara. I’m also iffy on the lovely pommel and quillons decorations but the guard is a thin plain sheet. To my eye this combination doesn’t fit together.

[werecow]

Originally Posted by Teisani

Found something with a nearly identical blade...

Also still on sale.

Radboud's kaskara suggestion is certainly feasible though. Maybe a picture of the peen could tell us something more about whether the blade is likely to have been rehilted?

EDIT: Adding a random kaskara from the intertubes for reference. The central fuller does sometimes run longer up to the full length of the blade.