During the rule of the Cholas in the eleventh century, the Tamils living in the Island were able to consolidate their positions in the militia and the administration of the Sinhalese kings. It may be assumed that more Tamils settled in the northern region during this period.
In 1215 AD, Magha of Kalinga conquered the Sinhalese kingdom with its capital in Polonnaruwa with the help of Dravidian soldiers. This invasion weakened the Sinhalese power to such an extent that any semblance of political unity in the Island disappeared.
Some maintain that events following the above invasion contributed to the development of the kingdom of Jaffna.
The fact that the Tamil invaders from South India ruled over the entire region of Nagadipa is significant. One assumes that there was support for them among the people of the Peninsula. Swami Gnana Prakasar’s opinion that the people of Nagadipa or Jaffna who were “never fully reconciled to the new belief [Buddhism] which came to be firmly established under Devanampiya Tissa (247-207 BC) and who had constant communication with the Tamils of the mainland… nurtured a spirit of revolt and were only too ready to stretch out a helping hand to any adventurer who would attempt to curb the sovereign power of the Sinhalese” may offer a clue to the success of some South Indian invasions.
After Magha, the Javakas led by Chandrabhanu came to power with the help of Tamil soldiers from South India and ruled over most of the territory that were previously under Magha. Chandrabhanu became almost a vassal of the Pandyas and was overthrown by themwhen he refused to send tribute.
As far as Jaffna was concerned, the legendary story of a Chola princess called Marutapuravalli marrying the king of Katiramalai is remembered in the later chronicles. One does not hear any more of Katiramalai, a fact which may point to a change of capitals.
In this period, migration from South India to Jaffna and the mainland of the North called Vanni seems to have been taking place. Pachilaippalli, an arid tract with sandy passes, became a central spot facilitating perhaps migrations to Vanni.
A new type of pottery classed as Grooved Rim Ware appears on the scene. Two Chola inscriptions belonging to the eleventh century, recording the imprisonment of the Sri Lankan King and the grant to a Nallur temple respectively, have been found in the Peninsula”
As far as religion was concerned, a brand of syncretism combining Buddhist beliefs and practices with Tamil Saivism and folk religion took place. Aiyanar was syncretised with Buddha.
In coure of time Buddhism was, on the wane. It was perhaps at this juncture that Saiva Siddhanta became the official religion of the Jaffna ruling class.
The eleventh to the fourteenth centuries witnessed a flurry of foreign and local trade. Many coins and Chinese ware of this period, a Tamil inscription of Parakramabahu I found at Nainativu and the observations of the Arab traveler Inn Battuta (14th century AD) about Jaffna corroborate this state of affairs.
By the end of the 13th century and not later than 1325 AD, the Tamil Kingdom of the North had “come on to the historical scene”.
This Tamil Saiva Kingdom, based partly on agrarian and partly on mercantile structure, had as its nucleus Uttaradesa, namely the northern division of Rajarata covering the areas of the northern part of the country.
The Kings of the Kingdom of Jaffna are known by the name of Arya Chakravartis. According to some, the descendants of Arya Chakravarti, a chieftain from the Pandya kingdom who became ruler of the northern part of the Island towards the end of the thirteenth century, came to be known as Arya Chakravartis. According to others, Jayabahu,who ruled the North while Magha ruled from Polonnaruwa, was probably the founder of the Arya rulers of the North. These rulers were originally a branch of the Ganga dynasty from Kalinga who had immigrated to Rameshvaram, South India, and had intermingled with the Brahmins of the area. It was to highlight their connection with the highest caste that they called themselves Aryas. Another school holds that Singhai Aryan, also known as Kulankaic Chakravarti, was the founder of the line of Arya Chakravartis. He was none other than Magha, alias Kalinga Magha, alias Kalinga Vijayabahu, who conquered Polonnaruwa in 1215.
The centre of power of the Northern Kingdom was the Jaffna Peninsula and hence it was known by the name of the Kingdom of Jaffna. Ibn Battuta, the Arab traveler who visited the capital in 1344 AD states that the Tamil King’s power extended up to Puttalam and that he was in control of the pearl fishery.
In the middle of the fourteenth century, the army of the Tamil King had penetrated as far south as Gampola and had driven the reigning Sinhalese King from his capital.
In the fifteenth century, however, there was a brief Sinhalese revival and the Kingdom of Jaffna was under Sinhalese rule for about seventeen years till the defeated Tamil King reconquered his kingdom with the help of the Tamil military chiefs from South India.
Under the Viljaya Nagara Empire of South India, the Tamil kingdom became its tributary and there followed a protective relationship. After its decline, Jaffna came under the sway of Tanjore and Madurai, two centres of power that succeeded the former Empire.
It is appropriate here to mention four factors, which contributed to the growth of the Tamil Kingdom.