City pillars located at the center of the muang were common to early Tai communities. The phallic looking poles are thought to represent the shoot of a rice plant, and possibly originate from an early fertility cult.
Under Brahmanic influence, city pillars took on added significance through association with the cosmological center of the universe. In Chiang Mai, the influence of Buddhism is clearly shown by the standing Buddha image placed upon the pedestal of the city pillar itself.
The city pillar is the home of guardian spirits for the city and must be venerated each year. The people of Chiang Mai make offerings of incense, flowers and candles during the Inthakhin festival, to bring prosperity to themselves and the city.
The festival begins with a procession of the Phra Fan Saen Ha Buddha image around the streets. Lanna people believe that a guardian spirit resides in the image, and that bathing the image with lustral water encourages rain.
See also: [The power of city pillars]