In view of the above, it is clear that effects of Magha's invasion was responsible for the development of two Kingdoms; that of Jaffna for the Tamils and that of Dambadeniya for the Sinhalese; and a number of autonomous or independent chieftaincies, collectively known as the Vanni chieftaincies. Most of the chieftaincies were under the authority of Tamil feudal chiefs called " Vanniar ". The Kingdom of Jaffna had as its nucleus, " Uttaradesa ", the nothern division of the old principality of Rajarata, and corresponding to the Tamil districts of the nothern part of the island. According to two semi-historical Tamil works - the " Yalpana Vaipava Malai " and the " Kailaya Malai " - the Jaffna Kingdom was founded by a line of kings who called themselves " Arya Chakravartis ". They ruled the independent Jaffna Kingdom from Nallur since 13th Century AD. Prof. K. Indrapala further states; 

"...... no genuine traditions of the Tamil settlement or invasions were preserved by the Tamils until they established a stable kingdom in the 13th Century ".

A further development following the fall of Polonnaruwa was the gradual abandonment of the irregation works of the North Central plain in the dry zone. The once fertile and prosperous North-Central plain which supported a flourishing society reverted to jungle and became an effective barrier between the Sinhalese and Tamil Kingdoms, which, for the most part, developed in isolation.

In the second half of 14th Century, the fortunes of the Sinhalese reached their nadir. As Sinhalese power in the island declined, the Tamils moved southward to exact tribute from the southwest and central regions, and the Tamil Kingdom kept up a steady and relentless pressure on the Sinhalese especially on the border regions. By the middle of the 14th Century, the Jaffna Kingdom had effective control over the northwest coast of the island upto Puttalam, and it seemed poised for the establishment of Tamil supremacy in Sri Lanka. These ambitions were thwarted primarily because the Jaffna Kingdom was soon embroiled with the powerful " Vijayanagar " empire in a grim struggle for survival against the latter's expansionist ambitions across the Palk Straits. The Tamil Kingdom was drawn irresistibly  into the orbit of the dominant South Indian State of the day. The second factor was the resilience and extraordinary recovery of the Sinhalese under the founder of the Kotte Kingdom, Parakramabahu VI, who successfully resisted the establishment of Vijayanagar power in the north of this island, and then proceeded to bring the Jaffna Kingdom under his sway. His control lasted for over two decades, but on his death, his political legacy was rapidly exhausted by his successors, and by the last quarter of the 15th Century, the Jaffna Kingdom had recovered its independence. Its survival was ensured by divisions within the main Sinhalese Kingdom - the Kingdom of Kotte - and by the rise of the Kandyan Kingdom which over the next two centuries inherited the mental of Kotte and became in time the last surviving Sinhalese kingdom in the island's history. It was an age of political instability and shifting boundaries of these several states, sometimes expanding and sometimes contracting in responce to the pressures of its rivals. Nevertheless, it would be true to say that by the begining of the 16th Century, the Jaffna Kingdom was the weakest of them all.