Kalinga Magha or Gangaraja Kalinga Vijayabahu was an invader from the Kingdom of Kalinga who usurped the throne from Parakrama Pandyan II of Polonnaruwa in 1215. A massive migration followed of Sinhalese people to the south and west of Sri Lanka, and into the mountainous interior, as they attempted to escape his power. Magha was the last ruler to have his seat in the traditional northern seat of native power on the island, known as Rajarata; so comprehensive was his destruction of Sinhalese power in the north that all of the successor kingdoms to Rajarata existed primarily in the south of the island.

Poḷonnaruwa, also referred as Pulathisipura and Vijayarajapura in ancient times, is the main town of Polonnaruwa District in North Central Province, Sri Lanka. The modern town of Polonnaruwa is also known as New Town, and the other part of Polonnaruwa remains as the royal ancient city of the Kingdom of Polonnaruwa.