What is Dressage?

According to Wikepedia - DRESSAGE
(a French term meaning "Training")
is a path and destination of competitive
horse training, with competitions held at all levels
from amateur to the Olympics.  
It's fundamental purpose is to develop, through standardized progressive training methods, a horse's natural athletic ability and willingness to perform, thereby maximizing it's potential as a riding horse. 
At the peak of a dressage horse's gymnastic development, it can
smoothly respond to a skilled rider's minimal aids by performing the
requested movement while remaining
relaxed and appearing effortless. 
For this reason, dressage is occasionally
referred to as "Horse Ballet."