1. Coins of pre-Satavahana chieftains and of the Satavahanas from Andhra- Karnataka region. The coins issued by the Cheras, Cholas, Pandyas, and the chieftains of the Sangam Age.
2. Roman copper, silver and gold coins.

Kizhar:
Kizhar were the heads of the villages or a small territory, later known as nadu. They were the chiefs of tribal communities living in specific areas. The Vendar were kings controlling larger, fertile territories.
Velir:
The Velir, who were many in number, controlled the territories of varied geographical nature, mainly hilly and forest areas, that were in between the muvendar's fertile territories.

Hiranyagarbha literally means golden womb. A person coming out of this golden womb, after elaborate rituals performed by priests, is declared as reborn possessing a celestial body. The Satavahana king Gautamiputra Sathakarni performed this ritual to claim Kshatriya status.

Karikalan's foremost military achievement was the defeat of the Cheras and Pandyas, supported by as many as eleven Velir chieftains at Venni. He is credited with converting forest into habitable regions and developing agriculture by providing irrigation through the embankment of the Kaveri and building reservoirs.

Tamilagam was divided into five landscapes or eco-regions namely Kurinji, Marutam, Mullai, Neytal and Palai

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.