Phra That Si Song Rak was built in 1560 A.D. as a symbol of friendship between Somdet Phra Maha Chakkaphat of Ayutthaya and Phrachao Chaiya Chetthathirat of Lan Xan, the two kings. It was at this spot that the two kings vowed not to invade each other’s territory, instead they decided to unify their armies so that they could fight as one against the invading army from Burma, present day Myanmar.
Built off the Laos-Thai border, the temple is located 83 kilometers from Mueang district. It is situated on a hill next to the Man River at border of the two ancient kingdoms in present day Dan Sai District of Loei Province. The chedi of the temple is 30 meters high and is built from brick and mortar. The Chedi has a 12-cornered indented square base giving it a cubical lotus shape, which is similar to Phra That Phanom in Nakhon Phanom Province.
The people of the district hold a grand celebration at the temple on the 15th day of the waxing moon in the month of May. They offer 3 objects made from candle wax. This is the best time to visit this unique temple, which symbolizes friendship and unity.
Visitors visiting the temple should be careful not to wear red or offer red flowers, as red symbolizes violence and blood. It is important to remember to remove ones hat, cap and shoes within the compound of the temple.
This temple is highly revered in Thailand and its most notable feature is its plastered stupa which houses the holy relics of Buddha.
The importance of this temple in the history of Thailand can be judged by the fact that Loei Province uses the image of the stupa in its provincial seal.