Overview
Before there was a Thai kingdom there was a long sequence of cultures in the same river plains, and their dress was the wrapped, unstitched clothing of monsoon Asia under Indian influence. What the Thai inherited when they moved south in the thirteenth century was already a settled way of dressing, and they kept it.
Key garments and style
The basic garment is a length of cloth wrapped at the waist — worn as a skirt, or drawn between the legs and tucked behind for work — with the upper body bare or crossed by a shoulder cloth. Nothing is cut to shape and nothing is fastened but by tucking and tying, which is the same principle that runs through Sukhothai, Ayutthaya and after.
Indian religion brought Indian iconography, and the Dvaravati and Khmer sculpture of these centuries is the evidence: stone and terracotta figures in thin clinging cloth, heavy ear ornaments, beaded collars and elaborate crowns on divine figures. Because the images are religious, they show idealised and ceremonial dress rather than what a farmer wore.
Earlier still, the Bronze Age cemeteries at Ban Chiang in the north-east yield the ornament rather than the cloth — bronze bracelets and anklets, glass and stone beads — with textile traces surviving only where they corroded against metal.
Transition
When the Thai founded Sukhothai in the thirteenth century they adopted this wrapped tradition wholesale, and the chong kraben and the shoulder cloth became Thai dress.