Rock and copper inscriptions are reliable sources of Kerala history. They speak about the history of kingdoms, dynasties and the political, social and cultural lives of the people. The evolution of the Malayalam language, alphabets, grama sabhas, coins, rituals, superstitions and power structure can be learnt from them.
The inscriptions also speak about the development and evolution of Malayalam and ancient alphabets. The language of many of the inscriptions is Malayalam and the alphabet is Vattezhuthu. Some inscriptions are in Tamil and Sanskrit (grantha alphabet) while others, a combination of Sanskrit and Malayalam.
When kings, members of the administration committees or other individuals donate land or other valuables to a temple, they were inscribed on the temple walls. The temples had a "Porkoyil Achari" who makes the inscriptions. When the temples underwent renovation, the inscriptions were copied and replicated on the new walls. Several temples across Kerala has rock inscriptions in the Vattezhuthu alphabet dating back to the ninth century.
Copper plates, the basic document for the rock inscriptions, were discovered from some places. The rock inscriptions were made as the people thought they would exist for long.
The inscriptions discovered in Kerala are short when compared to those in other parts of the country. The inscriptions in Kerala usually excluded details.