The legend of 'Parayi petta panthirukulam' is centred on Trithala. According to this story, a Brahmin named Vararuchi, married a lower caste woman without knowing her true identity(?). After the marriage, they set out on a long journey. During the course of the journey, the woman became pregnant several times, and every time she delivered a baby, the husband asked her to leave it there itself. Each of the babies was taken up by people of different castes (totally 12), thus they grew up in that caste, making the legendary 'Panthirukulam'. They all became famous in their lives and many tales are attributed to them. The eldest was Agnihothri, a Brahmin, whose place is Mezhathur in Trithala. The others are Pakkanar (basket weaver), Perumthachan (Master carpenter), Naranathu Bhranthan (an eccentric but divine person), Vayillakunnilappan (a child without mouth, whom the mother wanted to keep with her) and so on. Their stories are mentioned in the well known book 'Eithihyamala' by Kottarathil Sankunni.

The Siva temple, probably built during the 9th and 10th century, marks the transition from the Chola to the Pandya style of architecture. According to a legend, the child Agnihotri was bathing in the river along with his mother. He heaped the sand in the form of a mound on a plate ('thalam' in Malayalam). When the mother tried to remove the sand, she found that it has solidified in the form of a 'Siva Lingam'. Thus the deity is known as 'Thalathilappan', meaning God in a plate. The idol is said to have the constitution of sand. It is believed that the sharp bend in the river in the area was formed due to the river changing its course on its own, to give space for the temple to be built.

V. T. Bhattathiripad, Dramatist and a prominent freedom fighter
Maha Kavi Akkitham Achuthan Namboothiri
Thrithala Kesava Poduval, Thayambaka Maestro
M. T. Vasudevan Nair, Malayalam Writer & Jnanpit Award Winner
E. Sreedharan, Former Managing Director of DMRC
Ammu Swaminathan, Courageous freedom fighter and a prominent leader
Captain Lakshmi Sahgal, Activist of the Indian independence movement
Major Ravi, Malayalam film director