Muay Thai is the history of the Thai people and both are difficult to discover because when the Burmese army sacked and razed Ayuddhaya to the ground, the archives of Thai history were lost. With them, much of the early history of Muay Thai also went. The little we do know, comes from the writings of the Burmese, Cambodian, early European visitors and some of the chronicles of the Lanna Kingdom - Chiangmai.

What all sources agree on, is that Muay Thai began as a close combat battlefield fighting skill and many years ago national issues were indeed decided by Muay Thai contests. The first great upsurge of interest in Muay Thai as a sport, as well as a battlefield skill, was under King Naresuan in 1584, a time known as the Ayuddhaya period. During this period, every soldier trained in Muay Thai and could use it, as the King himself did. Slowly, Muay Thai moved away from its root in the 'Chupasart' and new fighting techniques were evolved. The change in the art was to continue under another fighting King - Prachao Sua - the Tiger King. He loved Muay Thai so much that he often fought incognito in village contests, beating the local champions. Thai Boxing became the favourite sport and pastime of the people, the army and the King. Historical sources show that people from all walks of life flocked to training camps. Rich, poor, young and old all wanted some of the action. Every village staged its prize fights and had its champions. Every bout became a betting contest as well as a contest of local pride. Muay Thai has always been a sport for the people as well as a military fighting skill. In all its golden ages, the people have trained and practiced the sport whether they were King or commoner. In fact it was a part of the school curriculum right up to the 1920's when it was withdrawn because it was felt that the injury rate was too high. The people however, continued to study it in gyms and clubs, just as they do today.

During the reign of the Tiger King, the hands and forearms began being bound with strips of horse hair. This was to serve a dual purpose - protect the fighter and inflict more damage on the opponent. Later, these were replaced by hemp ropes or starched strips of cotton. For particular challenge matches and with the fighters agreement, ground glass was mixed with glue and spread on the strips.
The changes that the sport has undergone have been changes to equipment used rather than radical change. For example, Thai fighters have always worn groin guards. A kick or knee to the groin was a perfectly legal move up until the 1930's. In the early days, the protection was made from tree bark or sea shells held in place with a piece of cloth tied between the legs and around the waist. The 1930's saw the most radical change in the sport as it was then that it was codified and today's rules and regulations were introduced. Rope bindings of the arms and hands were abandoned and gloves took their place. This innovation was also in response to the growing success of Thai Boxers in international boxing. Along with the introduction of gloves, came weight classes based on the international boxing divisions. These and other innovations - such as the introduction of five rounds - substantially altered the fighting techniques that the boxers used causing some of them to disappear. Before the introduction of weight classes, a fighter could and did fight all comers regardless of size and weight differences. However, the introduction of the weight classes meant that the fighters were more evenly matched and instead of there being one champion, there became one for each weight class.