The sources that furnish information to the historian can be broadly classified into two categories namely the literally sources and the archaeological sources.
Literary sources mainly refer to old book, manuscripts and maps. Before the invention of paper, books and manuscripts were written on materials such as birch, palm leaves, sheep leather, wood blocks and stone tablets. These are now preserved in various libraries and museums. The literary sources may be further sub-divided into religious literature and non-religious secure literature.
Religious literature refers to books and manuscripts dealing with religion. The religious literature of the Hindus includes the Vedas, the epics Ramayanas and the Mahabharata as well as the Puranas. These works were written in Sanskrit language. One of the important specimens of the religious literature of Tamil Nadu is the Periya Puranam. It deals with the life stories of the Nayanmar saints (devotes of Lord Siva) All religious texts throw light on the spiritual aspect as well as socio-cultural and economic life of the people.
Secular Literature refers to books and manuscripts on subjects other than religion. Secular literature includes books on law and polity. One such notable book is Arthasastra by Kuatilya. Law-books called Dharmasutras and Smritis together with their commentaries are called Dharmasastras. These books list the duties and responsibilities of people belonging to different professions. The books also prescribe punishments for persons guilty of crimes such as theft and murder. Among the important secular texts of south India, are some of the old Tamil poems such as Tirukkural. These poems were mostly composed in formal assemblies or gatherings of poets and scholar.
Oral traditions such as proverbs, nonsense rhymes and mythological legends also constitute a valuable source of information for the historian. You too may have heard some such stories and rhymes from your parents and grand-parents. Such oral sources are, however, not considered as reliable and authentic as the written sources because the oral stories are subject to change while being told and retold by different people.
Apart from the indigenous literature, the writings of foreign scholars and travelers are also useful for reconstructing the history of ancient South India. The ancient Indians traded with many far-off lands including Greece and Rome. The Greece and Roman sailors and travelers who visited India have left valuable accounts of the people here.
Archaeology is a specialized science dealing with the material remains of ancient civilizations. Archaeologists systematically and scientifically excavate ancient site and unearth interesting materials such as coins, vessels, terracotta toys, beads, jewellery and rarely, even ruins of old buildings. These materials throw light on day-to-day life of the ancient people.
Archaeological sources include monuments, art objects like paintings and sculptures, inscriptions or epigraphs and coins. South India boasts of the largest volume of inscriptions in the whole world.