1. Tamil texts including the Sangam and post-Sangam literature
2. The Arthasastra, the treatise on economy and statecraft authored by Kautilya
3. The Puranas which mention the genealogy of the Andhras/Satavahanas
4. Buddhist Chronicles such as Mahavamsa.
5. Gatha Saptasati, a Prakrit text composed by the Satavahana king Hala

Foreign Notices
The following Greek and Latin sources inform us about the long distance cultural and commercial connections.
1. The Periplus of Erythrean Sea, an ancient Greek text of the first century CE.
2. Pliny the Elder's Natural History, first century CE
3. Ptolemy's Geography, second century CE
4. Vienna Papyrus G 40822, aGreek document datable to the second century CE.
5. A Roman Map called Peutingerian Table

1. The period between the Sangam Age and the Pallava-Pandya period, roughly between c. 300 CE and 600 CE, is known as the age of Kalabhras in the history of Tamizhagam.
2. A group of inscriptions found at Pulangurichi in Sivagangai district datable to about the middle of the fifth century, name two kings. They are Chendan and Kurran. Though there is no mention about their family or dynasty name, some scholars identify them as Kalabhra rulers.
3. The Kalabhra kingdom seems to have been uprooted by Pandyas around the third quarters of sixth century CE.

A closer look at the Sangam literature reveals that social differentiation is evident in the Marutham region.
1. The territorial associations are very clear in the case of the Muvendar, and their important position is corroborated by the Greco-Roman texts from the first century CE.
2. Warfare for territorial expansion was a major theme of Puratthinai
3. Evidence for taxation at the highways and in the port of Kaviripattinam is cited.
4. The Chera king is spoken as receiving the resources from the hills and the port of Musiri.
5. Trade played an important role between the late first century BCE and third century CE.

The polities of the Cheras, Cholas and Pandyas were pre-state chiefdoms. The arguments for the latter view are:
1. No social stratification is noticed.
2. Proper territorial association is absent.
3. Destructive warfare did not allow the development of agriculture and surplus production for the emergence of the state.
4. No evidence of taxation as in the governments of North India.