I would recomend to start lunging when the horse is three years old. If you do it any younger it can be hard on the horses muscles. If you want to do it younger than three then it's better to do a...
The line is from Shakespeare's play, Richard III (Richard the third). In the middle of a great battle, King Richard has lost his horse and finds himself afoot. In desperation, he cries out, 'A horse!...