The temple was first established in 1383 under King Keu Naone and enjoys a fantastically mystical birth story. A visiting monk from Sukhothai instructed the Lanna king to take the twin of a miraculous relic (enshrined at Wat Suan Dok) to the mountain and establish a temple. The relic was mounted on the back of a white elephant, which was allowed to wander until it 'chose' a site on which a wát could be built to enshrine it. The elephant stopped and died at a spot on Doi Suthep, 13km west of Chiang Mai, where the temple was built in the year of the goat.
Read more: http://www.lonelyplanet.com/thailand/chiang-mai-province/chiang-mai/sights/religious/wat-phra-that-doi-suthep#ixzz2s5w8VVQo