The Thrissur Pooram, celebrated in the Malayalam month Of Medom (April-May) is a grand assembly of Gods and Goddesses in and around Thrissur. These Gods and Goddesses make their visit to the Vadakumnathan Temple premises on caparisoned elephants accompanied by grand ensembles of Chenda melam and pancha vadyam.The Ten participants of the Pooram are the Thiruvambady Bhagavathi and Paramekkavu Bhagavathi, Nethilakkavu Bhagavathi, Karamukku Bhagavathi, Ayyanthole Bhagavathi, Laloor Bhagavathi, Choorakkattukavu Bhagavathi, Chembukkavu Bhagavathi, Panamukkumpally Sastha, Kanimangalam Sastha. The processions and rituals of each of these deities follow a very strict itinerary, scheduled in such a way that the tempo of the Pooram celebrations – 36 hrs non-stop- is maintained without any loss of energy.
Very many stories are told and retold about the origin of Thrissur pooram. Thrissur pooram is 200 plus years young and before that the “Arattupuzha pooram” conducted at Arattupuzha, some 16 km away from Vadakumnathan was the biggest temple festival of Kerala. All the temples participating Thrissur pooram and Kuttanellore pooram was the regular participant of ”Arattupuzha pooram” .Once these temples were delayed to attend the festival due to heavy rain or so and then chief of Peruvanam Gramam denied the entry .As an act of reprisal Thrissur Naduvazhi the chief of Vadakunnathan, known as Yogadiripad and Kuttanellur Naduvazhi started the pooram in Thrissur. Later due to some reasons the Kuttanellur Naduvazhidisassociated the celebration at Thrissur. Since the withdrawal of Kuttanellur Naduvazhi the glamour of the pooram was lost and the two ‘Naduvazhies’ began to treat each other as enemies. It was in this juncture the former ruler of Cochin, His Highness Ramavarma Raja, popularly known as Sakthan Thampuran (1751-1805 AD) became the Maharaja of Kochi. Sakthan Thampuran unified the 10 temples situated around Vadakumnathan temple and took steps to celebrate Thrissur Pooram as a mass festival. Sakthan Thampuran classified the participants in to two groups the western and the Eastern The western group consist of Thiruvambady, Kanimangalam, Laloor, Ayyanthole, and Nethilakkavu temples. Paramekkavu, Karamukku, Chembukavu. Choorakottukavu and Panamukkamppilly comes under eastern group. The Maharaja re - organized the annual festival in its present form in front of Vadakumnathan. Sakthan Thampuran also directed the main temples at Thrissur, Paramekkavu and Thiruvambadyto extent all support and help to other poorams which are coming from 2 to 10 KM. away from Vadakumnathan temple. Recentaly the Kanimangalam changed to eastern side .The event management of the whole pooram was chalked out by His Highness Sakthan Thamburan and followed iota till now.There is an epilogue to the “ Arattupuzha “ pooram participation . While the Arattupuzha pooram has a history of more than 1000 years , Paramekkavu temple is 600 years old and Thiruvambady is still younger.Further Thiruvambady bagavathy , Paramekkavu baghavathy and Neithalkavu bagavathi are “ Bhadra kali”deities.. Only Sastha’s or Durga’s are the participant of Arattupuzha pooram. The other seven participients of Thrissur pooram which’s ancientry dates back to early 8century A.D and are Sastha or durgha cult , may be regulars to Arattupuzha.