The Rajarata civilization of Sri Lanka ended with the fall of Polonnaruwa to Kalinga Magha, a conqueror from the Eastern Ganga dynasty.
Parakramabahu II, who became the second monarch of Dambadeniya in 1236, was strengthening his army during the time to defeat and banish Magha from Sri Lanka.
While preparing for the battle with Kalinga Magha, Chandrabhanu, a Javaka or 'Malayan ruler' from the South-east Tambralinga kingdom[2][3] (present-day Thailand) invaded Sri Lanka in 1244 all of a sudden, with a host armed with blow-pipes and poisoned arrows.
Taking advantage of this opportunity, King Chandrabhanu gathered a large army from the north and invaded Dambadeniya to capture the Tooth Relic.
However, to further the Tamil hard power in the region,[6] they eventually installed one of their ministers in charge of the invasion, Kulasekara Cinkaiariyan, an Aryacakravarti as the King.
Jaffna then existed as a tributary state to the Pandyas and received independence in 1323, after the Pandyan Empire was annexed by the Delhi Sultanate and subsequently by the Vijayanagaras.
Meanwhile, in Southeast Asia, Tambralinga was annexed in the late-13th century by the emerging Ayutthaya Kingdom, with the region being renamed as Nakhon Si Thammarat.