Pre-history
Starting from the Stone Age, Thrissur must have been the site of human settlement. This is evidenced by the presence of a megalithic monuments at Ramavarmapuram, Kuttoor, Cherur and Villadam. The Ramavarmapuram monument is in granite and is of Menhir type. The monument in Ramavarmapuram is 15 feet height and 12 feet 4 inches broad. From 1944, it is under the protection of Department of Archaeology. The monument is locally known as 'Padakkallu' or 'Pulachikkallu'. These menhirs are memorials put up at burial sites for the departed souls. They belong to the Megalithic Age of Kerala, which is roughly estimated between 1000 BCE and 500 CE. All such monuments have not been dated exactly. Some experts are of the view that these are the remnants of the Neolithic Age in the development of human technology. The Ramavarmapuram Menhir is also believed to be a monument belonging to the Sangam period in the South Indian history.Another monolithic monuments like Dolmens and rock-cut caves are at Porkulam, Chiramanengad, Eyyal, Kattakambal and Kakkad. According to historians, the Dolmens are burial sites. Though most of the monuments were well protected, the dolmen at Porkulam was in a neglected condition. The monument excavated under eminent Archaeologist B. K. Thapar, between 1949 and 1950, was under the Department of Archaeology. Another megalithic monument is situated at Ariyannur in Thrissur. This place has unravelled monuments such as the 'Kudakkallu' or 'Thoppikkallu' (Mushroom stones or Umbrella stones) and 'Munimada' (Saint's abode). The laterite hillocks of Ariyannur rise to about 50 metres. Another reference in Ariyannur dates back to early 15th century in the poem 'Chandrotsavam'.
Pre-Colonial history
The region can claim to have played a significant part in fostering the trade relations between Kerala
