According to the recorded history of the Thai people, the Xen Muong Festival began in the 13th century. The Xen Muong Festival of the Thai people is held to express gratitude and commemorate the gods who created the Muong (the name of the land where the Thai people live). At the same time, it is also an opportunity for the people here to pray for favorable rain, wind, and good crops; to send great wishes for a peaceful and prosperous life in the Muong village.

The Xen Muong Festival usually takes place when the white Ban flowers bloom in the mountains and forests of Yen Bai. It usually falls around January or February of the lunar calendar, depending on the year. At this time, the sun is warm and the rice fields are green and lush. The Xen Muong Festival is almost the same in many regions, but each Muong chooses a different location, method of implementation, and some different rituals.
For the Thai people in Muong Lo, the Xen Muong festival used to be held in the forbidden forest of the Muong, choosing the place with the largest banyan tree and surrounding it were the resting places of the deceased. Today, the Xen Muong Festival is held in the Nghia Lo Museum Branch area. Choose a place where a wooden pillar is buried deep underground, also known as the "Dac Muong" pillar.

The ceremony of the Xen Muong Festival of the Thai - Muong Lo people
In Muong Lo, the shaman Nghe - the person in charge of the divine power of the Muong chief and the Elders' Association organize the Xen Muong festival. Here, the Xen Muong Festival must have the shirt of a son of the original noble lineage or the incumbent to be used as a sacrifice. But at present, the noble title no longer exists, so the Thai Muong Lo people use the shirt of a communal leader as a sacrifice. The offerings are entirely contributed by the entire Muong people, and two to four buffaloes can be slaughtered for the ceremony.
In the "Xen Muong" worship ceremony, in addition to offerings such as brocade, silver bracelets, necklaces, and rolls of cloth, there must also be dishes made from buffalo meat. Usually, in the "Xen Muong" worship ceremony, two buffaloes (one black buffalo and one white buffalo) must be slaughtered for sacrifice.

Festival
At the end of the ceremony, the entire Muong participates in the festival, which is the most anticipated part. At this time, the Quan (liaison) brings drums and gongs to hang in the middle of a large open space to beat the opening drum. The festival will include collective folk games. The games that are often organized are horse racing, “to mac le”, “to regret”, throwing con, shooting crossbows… In addition, the Xen Muong Festival of the Thai - Muong Lo people also has many sports and folk games with strong Thai indigenous characteristics such as throwing con, cu fighting, walking on stilts, tug of war in the Muong style (to la), climbing trees (khun may), singing and responding…