As we look through our ancient history, Onam was started as a celebration venerating one of the ten avatars of Lord Vishnu – Vamana. Lord Vishnu disguised himself as a Brahmin and visited the Yaagam conducted by the great King of Kerala that time, Mahabali. Mahabali promised to give anything requested during the Yaagam. Vamana, the great Brahmin claimed 3 paces of land from Mahabali. The Brahmin grew so huge and claimed the Earth and Heaven with 2 footsteps. With one more footstep waiting to be given, Mahabali, one of the wise kings, as he promised gave himself to the Brahmin as a mark of his word. Once in a year, Mahabali promised to visit his people’s home and so came into custom the great festival, Onam.
The origin of Onam can be traced to the Puranas, like the Bhagvata Purana, Vamana Purana and so on. On this occasion the picturesque state of Kerala gives a symbolic welcome to their king, Bali. Houses are cleaned and decorated with flowers and lights. A fabulous display of fireworks turns the capital Thiruvananthapuram into a veritable fairyland. Sumptuous feasts are prepared. The eldest member of each family presents clothes to all the members of the household. The image of Vamana is installed in each house. Vamana is worshipped in the temple.