The Modern Art of Taming Wild Horses/Chapter 14
If you should want to lead your colt by the side of another horse, as is often the case, I would advise you to take your horse into the stable, attach a second strap to the colt's halter, and lead your horse up alongside of him. Then get on the broke horse and take one strap around his breast, under his martingale (if he has any on), holding it in your left hand. This will prevent the colt from getting back too far; besides, you will have more power to hold him with the strap pulling against the horse's breast. The other strap take up in your right hand to prevent him from running ahead; then turn him about a few times in the stable, and if the door is wide enough, ride out with him in that position; if not, take the broke horse out first, and stand his breast up against the door, then lead the colt to the same spot, and take the straps as before directed, one on each side of his neck, then let some one start the colt out, and as he comes out, turn your horse to the left, and you will have them all right. This is the best way to lead a colt; you can manage any kind of colt in this way, without any trouble; for if he tries to run ahead, or pull back, the two straps will bring the horses facing each other, so that you can very easily follow up his movements without doing much holding, and as soon as he stops running backward you are right with him, and all ready to go ahead; and if he gets born and does not want to go, you can remove all his stubbornness by riding your horse against his neck, thus compelling him to turn to the right; and as soon as you have turned him about a few times, he will be willing to go along. The next thing, after you have got through leading him, will be to take him into a stable, and hitch him in such a way as not to have him pull on the halter, and as they are often troublesome to get into a stable the first few times, I will give you some instructions about getting him in.