There is a symbolic legend to explain why Holi is celebrated as a festival of colours. The word "Holi" originates from "Holika", the evil sister of the demon king Hiranyakashipu. The festival itself is believed to have origins from the Prahlada-Puri Temple of Multan in the Punjab region. The original temple of Prahladpuri is said to have been built by Prahlada, Hiranyakashipu's son. King Hiranyakashipu, according to legend, was the King of Multan and had earned a boon that made him virtually indestructible. He grew arrogant, thought he was God, and demanded that everyone worship only him.
Hiranyakashipu's own son, Prahlada, however, disagreed. He was and remained devoted to Lord Vishnu. This infuriated Hiranyakashipu. He subjected Prahlada to cruel punishments, none of which affected the boy or his resolve to do what he thought was right. Finally, Holika - Prahlada's evil aunt - tricked him into sitting on a pyre with her. Holika was wearing a cloak that made her immune to injury from fire, while Prahlada was not. As the fire roared, the cloak flew from Holika and encased Prahlada. Holika burned, Prahlada survived. Seeing this, Hiranyakashipu, unable to control his anger, smashed a pillar with his mace. There was a tumultuous sound, and Lord Vishnu appeared as Lord Narasimha and killed Hiranyakashipu. The bonfire is a reminder of the symbolic victory of good over evil, of Prahlada over Hiranyakashipu, and of the fire that burned Holika. The next day when the fire cooled down, people applied ash to their foreheads, a practice still observed by some people. Eventually, coloured powder came to be used to celebrate Holi.