What Is The Ancient Sword For?

I found a diamond sword(it's has minecraft's usual model)In the desert I think near the invaded barracks

It says its untredable but I have the odd feeling that it's for something.I already tried smaking a zombie with it but it did 1 hp damage

So does anyone know what it is for?

 

Screenshots and coords?

 

A discovery, find a room full of statues with swords and you can do something with it there

 

At the almuj desert i don't exaclty remember the cords but it was near the barracks I think in a place that doesn't apear on the map

Is the place on a desert..Is it by any chance a place that says you can't enter it unless you have discovered everything?

 

The room with the statues is the same location where you got the sword.

 

Thank you! I got it to work it was a neat puzzle!