Footnotes:
(1) This statement we can find back in the epic poem Khun Chang Khun Phaen, in which the king articulates his claim to authority, he points to the fact of hierarchy and the role of protective spirits: "I’m the pillar of the land. Though someone may have powers, he cannot compete with me. It’s known throughout the city that the guardian deities protect the royal lineage. How can those who are mere servants of the royal dust crave the world?” (Baker, 2012)
(2) Phi stands for ghost or spirit.
(3) The pillar has a phallic character, which may derive from Shaivism, where the lingam is associated with the depiction of Shiva (cosmic pillar - cosmological centre of the universe, as in the Khmer). On the other hand, in the animistic view, the phallus is worshipped for its sensual and fertility longings. The phallic pillar could also represent the shoot of a rice plant and may have originated from an early fertility cult.
(4) Next to these three most important spirits are Jao Jetkup and Jao Ho Klong (the spirit of the drum tower). Another tutelary spirit of the city was Jao Ho Khrueang, the spirit of the storehouse for valuables such as the royal jewels. (Baker, 2012)(5) Atthap, from the Atharveda, the fourth Veda, originally an Indian text that served as a manual of mantras. In Thai usage, atthap came to denote the spiritual force of a place, especially in relation to defence.
References:
[1] Baker, Chris & Phongpaichit, Pasuk (2012). The Tale of Khun Chang Khun Phaen: Siam’s Great Folk Epic of Love and War.
[2] Kerdphol, Pornpun. The Changes in the Belief in Chiang Mai Pillars During the Rattanakosin Period, from 1782 to 1992. Thammasat University.
[3] Raendchen, Oliver (1998). The Thai lak: ritual and socio-political function. SEACOM Berlin.
[4] Baker, Chris & Phongpaichit, Pasuk (2012). The Tale of Khun Chang Khun Phaen: Siam’s Great Folk Epic of Love and War.
[5] Baker, Chris Pombejra, Dhiravat na Van Der Kraan Alfons & Wyatt, David K. (2005). Van Vliet's Siam. Silkworm Books. p. 114.