Originally Posted By: tsuwm


Another theory comes from the fact that in typical propriety the person or persons standing to the rear-left of a gentleman held power and were typically those directly second to him. The person or persons standing to the rear-right were considered to have no or less standing than those to the rear-left, such as aides, bodyguards, wives, etc., often holding this position for simple facility rather than societal importance. This tradition remains in military parades, with lieutenants standing to the rear-left of the commanding officer (when facing the advance). - wiki


So you have your leftenant and your rightenant?