Long time ago lanna people beliefs the floating of light and sacrifice offerings along the waterway is called "long sapao" or "loi ruea samphao fai". In the old days according to the legend of Lampang City of the palm leaf version of Ban Hong Temple of Lampang, in the Haripunchai era around the 14th Century, the town was invaded by a plague of cholera taking a great number of lives so people were evacuated from Haripunchai to Hongsawadi or Pegu of Myanmar and remained there for several years before returning.However, a number of them stayed on in Myanmar. Thus when they missed their kinfolks in Hongsawadi,
They arranged the custom of floating flowers and other sacrifice offerings in a boat or sapao in the Yipeng month. That is how the loi sapao or Loi Krathong festival was originated.
Loi Sapao in this manner has become an occasion for merit making and passing on the merit to the deceased relatives or for accruing merit for oneself for the next life. In the past, the people around Wualai Village of Tambon Nantharam, Mueang District, Chiang Mai helped make a sampao at a local temple. It turned out to be a big boat fixed on a bamboo raft filled with all kinds of practical items like pots, jars, clothing, and food.
During the twilight of Yipeng, they would carry the boat to be floated in the Ping River. The procession was a fun-filled one accompanied by gongs, drums and other musical instruments playing all the way to the river to float the boat. After the boat had been allowed to drift for a while, the poor people who waited in the water could come onto the boat and take whatever they wanted or could get.
Thus, this was actually another form of giving as merit making. Nowadays, the samphao group in Chiang Mai Municipality has revived the tradition of floating a sapao. The Municipality also provides some financial assistance for many temples to make sapaos for floatinig.