This festival

was organised once by the Kochi Raja and Zamorines (king) of Kozikode in connection with the Atham during the month of Chingam.

In the past there was a festival lasting for 28 days starting from the Thiruvonam day of Karkidakom (July-August) to the Thiruvonam day of Chingam (August-September) was conducted at Trikkakkara temple. The last ten days of this festival beginning from Atham to Thiruvonam was a grand mela.

story told is that Mahabali who once ruled the country with Thrikkakkara as his capital. To respect him, the Rajas of Kerala came to Trikkakkara and celebrated Onam. Their journey to thrikkakkara came to be known as Athachamayam.