A postilion or postillion is a person who rides a harnessed horse that is pulling a horse-drawn vehicle such as a coach, rather than driving from behind as a coachman does. This method is used for pulling wheeled vehicles that do not have a driver's seat, such as many ceremonial state coaches and artillery limbers and caissons. Postilion riders are generally arranged one rider for each pair of horses, riding the left horse.[1][2][3]
Originally the English name for a guide or forerunner for the post (mail) or a messenger, it became transferred to the actual mail carrier or messenger and also to a person who rides a (hired) post horse. The same persons made themselves available as a less expensive alternative to hiring a coachman, particularly for light, fast vehicles.