Gladius

On the Right Side

The gladius is probably the most famous Roman weapon: a short sword built for fighting at close quarters. It could cut, but its sharp point made it especially good for thrusting, particularly from behind a shield.

And yes, one thing looks odd to modern eyes: an ordinary Roman soldier carried his gladius on his right side, even though most troops were probably right-handed. It kept the sword clear of the big shield on the left. Centurions, though, are often shown wearing theirs on the left.

Drawing a sword from the right takes a little practice, but Roman soldiers had plenty of that.

Besides, when thousands of Roman soldiers do something the “wrong” way, eventually you have to consider the possibility that they know something you don’t.