Multiple ancient and medieval Tamil and Sanskrit works contain legendary accounts of lands in South India being lost to the ocean. The earliest explicit discussion of a katalkol (“seizure by ocean”, possibly tsunami) of Pandyan land is found in a commentary on Iraiyanar Akapporul. This commentary, attributed to Nakkeerar, is dated to the later centuries of the 1st millennium CE. It mentions that the Pandyan kings, an early Tamil dynasty, established three literary academies (Sangams): the first Sangam flourished for 4,400 years in a city called Tenmaturai (South Madurai) attended by 549 poets (including Agastya) and presided over by gods like Shiva, Kubera and Murugan. The second Sangam lasted for 3,700 years in a city called Kapatapuram, attended by 59 poets (including Agastya, again). The commentary states that both the cities were “seized by the ocean”, resulting in loss of all the works created during the first two Sangams. The third Sangam was established in Uttara (North) Madurai, where it is said to have lasted for 1,850 years.
Source: Kumari Kandam – Wikipedia