The earliest stone inscription with a reference on Kerala is the Edicts of Ashoka (BC 274-237). Kerala is mentioned as "Keralaputho" (meaning Kerala Puthra) in the second and thirteenth Ashoka Sthambhas. It may be noted that Kerala is not mentioned as "Cheram" while "Cholas" and the "Pandyas" are named as such.
The second inscription in the Edicts of Ashoka says charity hospitals for humans and animals were established in the neighbouring regions ruled by the Cholas, Pandyas, Satyaputra, Keralaputra and the Thambapanni (Sree Lanka). It also said that trees were grown and ponds were dug on the pathways for the sake of humans and animals.
The rock inscription was found to be installed at six locations. The thirteenth inscription in the Edicts of Ashoka says about the Dharma Vijaya achieved outside the kingdom of Ashoka.
The edicts say the kingdom of Ashoka extended till near Tamil Nadu. Some historians cite that the usage of plural names for referring to the dynasties - Pandiyar, Cholar, Keralaputhrar - point to the fact that they were tribal republics.