The art of warfare has dominated history since the origin of humans. The martial arts (in the connotation by modern society), however, began as a series of exercises to improve the health of ailing Buddhist monks. These exercises eventually developed into fighting skills when the monks discovered a potential to serve as "warrior priests," which helped them earn money to support their temples. Today, the martial arts can still serve as a self-defense tool or as a form of exercise. There are also styles that integrate traditional martial art forms with aerobics as a basis for modern cardiovascular training. Martial arts as a fighting style and as an exercise are practised by millions across the globe.