[2] This period was considered to be a golden age of cultural development in Lan Xang, and the arts flourished in Vientiane, the Lao capital.
[9] Up to the early 20th century, most works of literature in Laos were preserved through continuous copying in the form of palm-leaf manuscripts, traditionally stored in wooden caskets and kept in the libraries of Buddhist monasteries.
[10] One of the Sinxay palm-leaf manuscripts was discovered in the Thai National Library in Bangkok by Mahasila Viravong, a Buddhist and Pali scholar who worked there.
[11] In the 1980s, Mahasila began translating Sang Sinxay into modern Lao, hoping that a new prose edition would help future generations understand and enjoy the poem.
The new edition, titled Sinxay, was first published in 1991 by Dokked Printing Ltd, which is owned and directed by Douang Deuane Bounyavong, daughter of Mahasila Viravong.
Nang Lun gives birth to two twins: Sangthong (ສັງທອງ), who has the body of a conch shell, and Sinxay (“he who will triumph by his virtues”), who holds a sword, bow and arrows.
After enjoying the nariphon and having to fight the phanyathone, Sinxay comes upon Ton Kalapheuk, the mythical Wishing Tree, covered in jewels and hand woven silk textiles.
Soumountha then asks Sinxay to rescue her daughter, Sidachan, who is now the wife of Nak Valoonarat, king of the nagas and guardian of underworld treasures.
Sinxay and Sangthong are helped in the battle by the khut, and they finally prevail, capturing Nak Valoonarat, who agrees to hand over Sidachan.
Soumountha leaves her silk scarf, her ornamented hairpin and her hair extension by the river, praying they would be returned to the palace as proof of Sinxay’s survival.
Vedsuvan descends to earth, and pours sacred water on Koumphan’s bones, which were laid in a stupa after his funeral and cremation, bringing him back to life.
Siho slips Sinxay’s bow and arrows and sword through the bars, while Sangthong, who has become a frog, knocks over the iron cauldron, scalding the nearby nyaks.
Koumphan’s anger finally dissipates, and he agrees to travel to Muang Pengchan and ask for Soumountha’s hand in the traditional and customary way.
She accepts his proposal, they marry, and Koumphan builds a saphanthong, a golden bridge connecting the kingdom of nyaks with the humans, as a symbol of alliance.
Sinxay continues being the virtuous king of Muang Pengchan, with his kingdom now strengthened by the new alliances with the khuts, naks and nyaks..
Sang Sinxay is one of the poetic works which was meant to be read out loud on special occasions such as religious festivals, an art which became known as nangsu, a term which to this day is used to describe storytelling in Laos.
[4] The Abbot of Wat Chaisi, Phra Kou Yathanyakon, worked closely with the Khon Kaen Municipality to help implement summer programs for youth in the temple, expanding on the Buddhist teachings of ‘’Sang Sinxay’’.
In February 2010, during the celebration for the 450th anniversary of Vientiane, a special day was organized to commemorate Sinxay, with performances by the Children’s Education Development Center, displays of illustrations by students from local schools and various lectures about the hero.
At the time Sang Sinxay was written, the Lao kingdom of Lan Xang also encompassed the northeastern region of Thailand commonly referred to as Isan.
[3] Although Sang Sinxay was originally meant to be read out loud or sung, this oral tradition has declined, and the poem is now rarely chanted in temples.
One exception is the Lan Xang Heritage Group’s poem recital project, founded by Daravong Kanlagna, grandson of Mahasila Viravong.
In Vientiane, scenes from Sang Sinxay are carved on the front doors and the right side window panels of the temple of Wat Haysoke.
In Sam Neua a recently constructed temple, Wat Ong Teu, features gilded carvings designed by renowned Vientiane artist Bounseng Thiepphongthong.
In Isan or the northeastern part of Thailand, three temples host 'hup taem' murals featuring scenes from Sang Sinxay.
Wat Chaisi, proclaimed Ancient Monument by the King, has the most extensive murals, covering all four sides of the outer and inner walls of the sim.
The painting of the murals was overseen by Luang Po On Sa, a monk who wanted to motivate the laity who were too busy to study the dharma to be virtuous like Sinxay.
In Isan Sang Sinxay is one of the most commonly performed stories within the shadow puppet theatre tradition called Nang Pramo Thai, along with the Ramakien.
[22] The most well known troupe, called "Bong Beng" and led by Sombat Nyotbatum, performs Sang Sinxay about sixty times a year.
The poem was first translated into French by Nhouy Abhay and Pierre Somchinne Nginn in 1965, under the title Sinsay: chef-d’oeuvre de la littérature lao.
Another translation into French by Dominique Menguy, based on the 1991 modern Lao version, was published in two volumes in 2003 and 2004 under the name Sinxay: L’épopée de Pangkham.