Mamankam was held once in every 12 years at Thirunavaya, on the banks of the river Bharathapuzha. Celebrated for 28 days, it was also an enormous trade fair in which traders from various places came to Thirunavaya. At the grand finale, which was a great assembly of rulers, the new king of Kerala was selected. Two of the earlier kings who are known to have abdicated their thrones following this route were Kulasekara Alwar (8th century) and Cheraman Perumal (A.D 825).
With the rule of the Perumals coming to an end, the right to conduct Mamankam vested with the ruler of Valluvanad. As mentioned earlier, Mamankam was also an enormous trade fair and thus of high economical advantage for its controllers. This triggered bitter strife among the rulers over the right to conduct and control Mamankam. Later the Zamorin of Kozhikode, took this right by force and this resulted in dispute and bloodshed between these two kings. With this incident the basic purpose of Mamankam ( selection of new king ) changed and it became a game of revenge between the two rulers, in which the king of Valluvanad used to send Chavers (suicide warriors) to fight until death and recapture the right from the Zamorins. A Mamankam was held at the end of each 12th year. During this time, the Zamorin would stand waiting at the Nilapadu Thara surrounded by a huge contingent of soldiers and a battle was fought between the chavers and the soldiers of the Zamorin. The last Mamankam to be held at Thirunavaya was in 1755.
Events like Mamankam were unique to Kerala. Thirunavaya on the banks of Bharathapuzha is now an area of historical importance and the Nilapadu Thara is now under the control and protection of the Archeological Dept. It is also an important tourist spot.