The CCI**** was begun in 1998, and has been held annually since. Since 2000, the CCI**** is the only competition held during this time, and the preliminary, intermediate, and CCI*** levels are not offered. The Kentucky Three-Day Event also hoped to continue the classic format, despite the other major events around the world switching to the short format. Originally, the plan was to alternate years, offering the short format in even-numbered years as preparation for the Olympic games or the World Championship, while running the classic format in odd-numbered years. However, in 2006 it was announced that, due to lack of funds and interest from upper level riders, the event would only offer the short format. Therefore, all competition run before 2005 (excluding the 2004 Modified division) was run "classic format," and from the 2006 event onward has been run in the "short format." The CCI**** competition was first suggested in 1994 by Denny Emerson, who believed the United States had enough competitors at this high level to warrant the development of a four-star. Previously, American riders trained in England when they were preparing for international competition, as the country had the only two annual CCI**** at that time: Badminton and Burghley. The USET began making plans in 1996, and held the country's first and the world's third annual four-star competition at the Kentucky Horse Park in 1998. After the 2018 season, the FEI added an introductory level below CCI*, bumping all subsequent levels upward. While there was no change to the difficulty of the competition, the added level forced all former CCI**** competitions to re-classify as CCI*****. This sport takes many different precautions concerning the horse's health. Two horses died of a heart attack on the course in April 2008. Self-efficacy is a way to assess themselves and the horse using a scientific method. Evaluating the health of the horse is important because the horse could easily get injured. A study was done to compare the heart rate between a trained and untrained horse. The results show that trained horses do not have more stress or pain in comparison with untrained horses. However, if evaluated 30 minutes before competition, the trained horse would show less stress. According to this experiment the training method, "Deep and Round", put more stress on the horse.