King Meng Rai, a friend of King Ramkhamhaeng (1279-1299) of the Sukhothai Kingdom of Thailand, established Chiang Rai in 1262 A.D. near the Kok River. Thirty-four years later, he founded Chiang Mai as a capital city and centre of the Lanna Thai Kingdom (circa 1262-1558 A.D). Thus the two towns have had brotherly relations for a long time. The Lanna Thai Kingdom covered the area of Chiang Mai, Chaing Rai, Phayao,Nan and other provinces in the North of Thailand at present. The kingdom became a Burmese colony from 1558 to 1774 A.D.

But finally, King Taksin (1767-1782 A.D.), the king of Siam of the Thonburi period, won it back from the Burmese, and the Lanna Thai Kingdom became a dependency of Siam (former name of Thailand). And Chiang Rai was ruled as a frontier town until 1933 when it became a province of Siam.