If one were to take a cursory look at the history of these people as they wrote it down, they categorically state as a matter of fact that they are the inheritors of a civilization stretching back to 9,000 - 10,000 BCE. There were 3 "Sangams" or "civilization phases" that had to be relocated every 4,000 years or so due to rising oceans (or sinking land.) It has been dismissed as a legend or myth in spite of little to no marine archaeology undertaken in the area, in spite of bathymetric studies done by Prof. Glen Milne (quoted in Graham's "Underworld" with data and sea level simulation maps) that show the majority of the Sunda Shelf (the area between India and Indonesia) as being above sea level during the ice age, and gradually submerging between 9,000 BCE and present day in phases as sea levels rose.
According to the Sangam legends first described in the Irayanaar Agapporul (11th century AD) and a commentary to it by Nakkirar. There were three Sangams spanning thousands of years. The first Sangam, whose seat was then Madurai (southern Madurai), lasted a total of 4440 years and 4449 poets, which included some gods of the Hindu pantheon, took part in it. Lord Shiva presides it. The second Sangam was convened in Kapatapuram, which finds mention in Valmiki Ramayana (Kishkinda Kanda 42:13). This Sangam lasted for 3700 years and had 3700 poets participating. Both these places were held in legendary kumari kandam, which was submerged into sea. The third Sangam believed to be located in the current city of Madurai and lasted for 1850 years under 49 kings.