Eventing traces its beginnings to "The Militaire" in Europe. The demands of the equestrian " triathalon" were patterned after the training and testing of military chargers. The requirements were precision, elegance and obedience on the parade ground; stamina, versatility and courage on marches and in battle; cross-country jumping ability and endurance in traveling great distances over difficult terrain and crossing formidable obstacles in the relay of important dispatches; and jumping ability in the arena to prove the horse's fitness to remain in service. Run in consecutive days, the Three-Day Event was the ultimate test for the Army horse. Only active-duty Army officers mounted on military chargers were allowed to compete.

Three-Day Events were first introduced at the 1912 Olympic Games in Stockholm. Of the 27 competitors starting, 15 finished. Among the seven competing countries, the United States placed third, winning the bronze medal. By 1924, seventeen national teams competed in Paris; the United States was the only overseas competitor. It was in the 1924 Olympics that the present pattern for the Three-Day Event was established. The 1948 Games in London marked the end of the U.S. Army participation in Olympic equestrian events and the transition to a civilian competition. Olympic competition was opened to women in 1964.

Eventing (or combined training) has long enjoyed immense popularity with competitors and spectators alike in Europe. It is now attracting more and more enthusiasts in this country. American athletes--horse and rider--competed successfully at the 1992 Olympics in Barcelona. Even greater achievements were attained for the U.S. Equestrian Team (USET) at the 1996 Olympic Games in Atlanta where they won the Team Silver Medal. Eventing was featured prominently in news coverage of competition at the 1996 Olympics because of the success of the USET and the thrills of the combined training competition. Two members of the USET eventing team are husband and wife, David and Karen O'Connor.