@izzythepush,
izzythepush wrote:
It all boils down to carrying swords. You hang your sword on the left side of your body. You ride on the left, so your swords don't clatter against each other as you go over London Bridge.
I quite agree, although I don't think it had much to do with swords, hanging from the left hip, clattering against each other. The left hand side of the road habit started, I believe, to leave your right hand, i.e. your sword-weilding hand, free to engage in a fight against the man coming up on your right.
(Which makes me wonder where the rest of the world got into the quaint habit of traveling on the right -hand side of the road?)