Thai Buddhism is especially well-known for its emphasis on monastic discipline.  This includes not only a tradition of especially careful study and practice of the Vinaya rules, but also a custom of observing supplementary monastic traditions of homeless wandering and extremely simple living.  To judge by the reports of Chinese observers, this custom derives from the peoples of Indo-China who precede the arrival of the Thai in most areas of present-day Thailand and Laos.  It is also especially among the Tai peoples that many traditions of calm (samatha) meditation are still preserved and practised, including in some cases various forms of esoteric tradition as well as many popular ceremonies and ritual practices.

During the eighth and ninth centuries (and probably long before) the Tai peoples seem mostly to have inhabited the valleys leading from the South-East Asia lowlands to the Yunnan plateau where some still remain.  In the subsequent centuries they slowly moved southwards.  By the twelfth century they were able to supplant Mon rule in the northern part of present-day Thailand and push back the Khmer suzerains of Central Thailand.  The subsequent history can be seen as that of various kingdoms of various strength: eg. The Lan Na kingdom at Chiengmai, the Lan Sa kingdom in modern Laos, the Sukhothai and Ayutthaya kingdoms further south and Nakhon Sithammarat in the peninsular as well as many others. But it is probably more accurate to think of numerous city states and tribal polities, of differing ethnic complexion and in varying allegiance to whichever among them was the most prestigious.  The modern state boundaries and the concept of a state as such are not really applicable at this time. 
     During the sixteenth and seventeenth centuries, however, the Central Thai principality based at Ayutthaya emerged more and more strongly as a kingdom with a general, if loose, hegemony over most of the Tai peoples.  Despite competition with the similarly emerging Burmese monarchy, the Thai kings at their new capital of Bangkok  had become by the mid-nineteenth century rulers of a Siamese empire extending well beyond the boundaries of present-day Thailand.  Although pushed back by the new French and British rulers of Burma and Indo-China, they were still able to retain their independence and the larger part of their territories - the only South-East Asian state to do so.  A program of modernization and centralization formed the modern nation of Thailand during the course of the twentieth century.

Those of Southern Buddhism in general and also an orange flag displaying an eight-spoked wheel.

The Tai peoples as a whole number nearly 70 million, mainly in Thailand, Laos, and Burma but include significant populations in China and Vietnam and in a diaspora around the world, as well as smaller numbers in Cambodia, Malaysia and N.E. India.  The great majority of these adhere to the form of Southern Buddhism mentioned here, although some tribal peoples appear never to have adopted Buddhism and forms of East Asian Buddhism are found in a few areas.

Over the last century Bangkok has become far and away the most important centre, but there are many local centres of importance within Thailand and in Laos, Burma and neighbouring areas of China.