1813 26 Apr. 265/1 A well-known quack..appeared on poney-back.
1923 J. B. Harriman 20 The journey up in the spring we used to make on pony-back.
2001 (Nexis) 29 Oct. 20 He suffered 12 injuries, including the loss of half a leg, which forced him to trot into battle on pony-back.