BBB Etymology - Ride roughshod over

A horse is said to be roughshod when it has shoes with the nail-heads projecting so that it can get a better grip, in icy weather for example. Cavalry horses could also have shoes like this, not only to prevent them slipping and disrupting a charge, but also to inflict more damage on the enemy as they rode over them. It was from this practice that the expression to ride roughshod over comes; used literally from the 17th century, and by the 19th transferred to mean to domineer, to carry on regardless, trampling down other's opinions or desires.