In the past, we called Loi Krathong as Chong Pa Rieng- floating lantern of royal ceremony. It is a Brahman festival to worship Gods- Siva, Vishnu, and Brahma. When Thai people adopted Buddhism, they adapted this ceremony to honor the Buddhas cremated bone- the original Buddha at the second heaven ruler. They floated lantern to worship the foot-print of the Buddha on Nammathanati River beach in India.
Floating krathong along the river was created by Nang Noppamas; the most favorite concubines Sukhothai king. She made krathong as lotus-shaped. The king of Sukhothai floated it along the river. According to Sri Chula Lucks treatise, Phra Ruang (Sukhothai king) said From now on, on the full moon night of the twelfth lunar month, kings of Siam have to make floating lantern- like lotus-shaped- to worship the foot-print of the Buddha on Nammathanati River for ever after.
In Rattanakosin period, people often made big and beautiful krathong. According to Chao Phraya Dhipharachawongs historical annals said:-
In the twelfth lunar month on 14 and 15 waxing moon, I ask for members of the royal family and civil servants making big-sized krathongs- look like banana trunk rafts, they size 8-9 sauk width (an ancient Thai measure of length) and 10-11 sauk tall. They make for contesting each other. For example, some imitate krathong as Mount Meru – shaped and others make krathong as basket decorated with flowers. There are a lot of people to do these so they use a lot of money- about 20 chung (an ancient measure of weight).
Nowadays, Loi Krathong festival is held in mostly Thai provinces. Particularly in Chiangmai, it has krathong parade, contestation of making krathongs, and Noppamas beauty pageants contest.
The villagers in northern and north-eastern parts of Thailand often float lanterns. They are made of color paper. If they float in the afternoon, they will use smoke for floating lanterns while they use torch to set smoke in lanterns to float them in wind chill at night. We can see the light from lantern in the sky with moonshine and stars glitter at night, which is very beautiful.