I didn't let her walk him out and turn him by herself until after we had trotted with me running alongside, to make sure that she was pretty steady in the saddle. Then I transitioned her to a longe line so that the pony went in a circle around me, with the line through both sides of the bit so that I ultimately had control if things went south. She didn't go alone until she had learned to post a trot.
Also, this all took place inside an enclosure (a schooling ring) so that pony couldn't run far if he somehow took it into his head to be Seabiscuit for a Day.
Another alternative method would be to put the horse on a lead shank for added security. Some people "pony" - i.e. the adult rides a horse alongside the pony and holds the lead shank. Or you could use a longe line or two longe lines (sometimes called driving reins) and walk along behind.
As to what method was in use in those days, I bet it was more of "throw 'em off the dock and see if they can swim." I know that in England ponying on a lead line was most common, especially in the hunting field, but I don't think they were that formal in rural Virginia! Most kids were probably riding as soon as they could toddle, and had been "put up" on plow mules from infancy. I have a picture of my daughter at 18 months old sitting on top of a racing Quarter Horse (with several of us hovering in attendance).
Ponying
Two long lines - driving reins
Longing.
Hope that helps!
It helps beautifully. I thank you for helping me out with the horse details of my novel. For what is going on in the scene, I think put them up and lead them will be best. Thank you again!