Think this one is Spanish. See::
vicentetoledo.es/es/espadas/espadas-militaresIn this list there you find some variations of this type ranging from the 1780 model ESPADA Tropa de Caballería to the 1803 model.
The difference sits mainly in the type of blade. If I remember correctly the blade you have is the old (first) variant.
So you have a Spanish Cavalry of the Line troopers sword. Very nice find indeed.
If you click on the thumbnail of any sword in the list, you'll automatically download a nice PDF with all of the interesting facts.
It was some work, but I downloaded everything in Vincente's Espada and Sable list. Just in case this wonderful website disappears.
PC storage is cheap these days and those small PDF files are an easy fit on any thumbdrive too.
Markings:: I have to go to what I remember...
F = Fabrica (I think) and the Y :: T :: 17?4. Cannot read the ? but it could be 1784. Not sure.
This formula reads: Fabrica Y (in) Toledo (in) 1784.
R under crown. Royal arsenal most probably. And/or tax stamp.
The rest of the inscription is quite faded, but we see a III at the end.
Think this may be (King) Carlos III. The rest of this line before the Carlos III I cannot read, but it should be something like:
ESPADA Tropa de Caballería De Linea.
Vincente Momparlar may help you fill in the blancs.
Hope this helps you out a bit.
Cheers.
PS.
Turning the blade a bit while playing with the light source may enhance the script left.
Daylight can do wonders.
Sometimes this helps to bring out remnants of faded inscriptions. It's like playing with faint shadows.
For more interesting (Spanish) sites in the notes, see:
sbg-sword-forum.forums.net/thread/59625/spanish-espada-montar-oficial-circaand
sbg-sword-forum.forums.net/thread/58120/spanish-carlos-m1773-cavalry-swordI have two more in my little collection, but the notes of the above threads may be the more important.
Lots to sort out.
Have fun!