The problem with mounting swords on a wall, is the actual fixing. Either the sheath is fixed to the wall so that it is a permanent holder and as such part of the wall or it is removable so that it can be worn at some time in the future

The first means that you would have to have a second sheath if you ever wanted to wear it.

If it is removable then you will need a pair of brackets. Horizontal is the easiest. Two shelf brackets with no shelf. The sword and sheath rests on them both. If you want the sword to be mounted at an angle (45o or 30o is the usual), then the brackets need to be modified. The bottom bracket (point end) needs to have some sort of cup affixed so that the point cannot move around. The top bracket need only be a decorative pin of some sort (the sword is only resting on it). I have seen a 6" nail used with a concho stuck to the head. This needn't cost a fortune. A small (single serving) tin can could act as a cup. A bit of re-spraying and some camouflage and no one would know.