Human existence in the Indian subcontinent has been close to a million years. For 99% of that time period Sri Lanka was part of that common land mass, and only separated physically from south India around 6000 years ago1.
The people of South India and Sri Lanka therefore shared a common ancestry and culture during the stone age period.
The indigenous people of the island were the Veddahs. These hunter gatherers lacked West Eurasian DNA (Iranian farmer and Steppes ancestry) over 3000 years ago.
From 1000 BC onwards Early Iron Age culture spread from Tamil Nadu into Sri Lanka with the migration of likely Dravidian speakers. These Dravidian speakers descended from the ancestral south Indians and were the first inhabitants of the Jaffna peninsula which was uninhabited in the stone age.
Ancient Tamil and Pali literature refers to these people as the Nagas. In the rest of the island the Nagas mixed with the indigenous Veddahs.
In Jaffna the skeletal remains of an Early Iron Age chief were excavated in Anaikoddai. The name Ko Veta is engraved in Brahmi script on a seal buried with the skeleton1.
Ko, meaning “King” in Tamil, is comparable to such names as Ko Atan and Ko Putivira occurring in contemporary Tamil Brahmi inscriptions of South India1.
From 500 BC onwards the island received a predominant North Indian cultural influence. There was likely migration of North Indian elites who mixed with the local population, paving the way for Prakrit to replace the local languages. Buddhism was introduced by Emperor Ashoka in the 3rd century BC and became the dominant religion throughout the island including in the North-East.
For over a millennium until the 10th century AD the people of the North-East were predominantly Buddhist and likely spoke Hela (Prakrit derived Proto-Sinhala).
Tamil later became the dominant language due to a process of language replacement largely stimulated by the Chola invasion of the 10th century1.
There is no archaeological or genetic evidence to suggest large scale population replacement in the North-East. There has been a basic continuum in population from the Early Iron Age to the present era, including the ancient Buddhist period.
Genetic studies points to most Sinhalese and Eelam Tamils sharing a common descent, with alleles specific to the island which are absent in south India, probably related to the North Indian input circa 500 BC2, 3, 4, 5.
Despite this all Sinhalese and Eelam Tamils cluster closest to South Indians genetically than any other population (including North Indians), suggesting that South Indian migrations account for their core ancestry.
Full translation of King Parakramabahu’s Tamil inscription from Nainativu, Jaffna6:
“…foreigners should come and stay at Urathurai, that they should be protected, and that foreigners from many ports should come and gather in our port; as we like elephants and horses, if the vessels which bring elephants and horses unto us get wrecked, a fourth share of the cargo should be taken by the Treasury and the other three parts should be left to the owner; and, if vessels laden with merchandise get wrecked an exact half should be taken by the Treasury and the other exact half should be left to the owner. This regulation shall be enforced as long as the sun and moon last. This regulation was caused to be inscribed on stone as well in copper. This regulation was framed and issued by Deva Parakramabahu who is like a wild conflagration unto the dynasty of enemy kings, the overlord of all Sinhala.”
The ruling Sinhala king of the 12th century issued edicts addressed to the local Tamils of the North and did not regard them as foreigners (in contrast to the foreign traders mentioned in the edict).
1. K. Indrapala, The Evolution of an Ethnic Identity: The Tamils in Sri Lanka C.300 B.C.E to C. 1200 CE, Vijitha Yapa, 2005
2. T.D. Praveen Tharanga et al – Genetic variants in the cytochrome P450 2D6 gene in the Sri Lankan population
3. Kshatriya GK, Genetic affinities of Sri Lankan populations, Human Biology, 1995
4. Ranasinghe R at al – A study of genetic polymorphisms in mitochondrial DNA hypervariable regions I and II of the five major ethnic groups and Vedda population in Sri Lanka. Leg Med (Tokyo) Nov 2015.
5. Mitochondrial DNA history of Sri Lankan ethnic people: their relations within the island and with the Indian subcontinental populations, Journal of Human Genetics (2014)
6. K. Indrapala - The Nainativu Tamil inscription of Parakramabahu I, University of Ceylon Review VoI XXI No. 1 1963, pp 63-70