I collect weapons, so finding a sword wasn't difficult for me. I chose one that had a somewhat crusader-shape aesthetic - i.e. it was cross-shaped (photo 1). If you don't have a sword, you can use a prop, or find a real one at many cutlery stores or museums.
I removed the center piece of the scabbard and fed a length of brown satin ribbon through it and closed it back down (photos 2 and 3). Make sure you use enough ribbon to wrap around your waist two or three times.
Congratulations, you can now wear your sword! Make a halo after the jump.