The ancient ports on Tamil Nadu coast have played a dominant role in the transoceanic trade and commerce with the Mediterranean and the Southeast Asian countries since very early times. Important ports such as Kaveripoompattinam, Mahabalipuram, Nagapattinam, Korkai, Alagankulam are noted not only for brisk maritime trade but also for the establishment of the Hindu kingdoms and spread of the Indian culture in the foreign lands from beginning of the Christian Era up to the eleventh century CE. Many such port towns that existed on the coastal region vanished or were submerged by the sea, maybe due to coastal erosion, sea level changes, neotectonic activities, etc. Ancient literary sources across the country refer to the submergence of prosperous cities. These traditions, like the submergence of the Golden City of Dwarka mentioned in the Mahabharata, the Sangam literature refers to the submergence of Poompuhar and popular beliefs about the submergence of the temples of Mahabalipuram, the ‘Kumari Kandam’ traditions of Tamil Nadu, etc., are well known as they are passed on from father to son as local traditions. It may well be impossible to search for their roots or find proof that such beliefs are based on facts. Nevertheless, many archaeological explorations have been taken up in an attempt to verify the historicity of these traditions.

Sangam literature, one of the richest ancient literary bodies, preserved in Tamil Nadu, gives ample historical accounts of maritime trade and commerce prior to the Christian era. Sangam literature mentions about the flourishing port town of Poompuhar, the capital of the early Cholas. The maritime trade with the Southeast Asian countries through the port of Kaveripattinam was confirmed with the item of Kalakam (Kalakattu akkam means ‘the goods from the place of Kalakam’) (Rajan, this volume). According to Nagaswamy (2007) Hindu images of Shiva, Vishnu along with Tamil inscription mentioning Nangur, Manigramattar, Avani Naranam and Sena mukattars were found at the ancient port town of Takuapa, Thailand; they prove close contact with the Kaveripattinam trade network and with the Pallava kings. The Manimekhalai mentions that Poompuhar was swallowed by the sea due to the wrath of goddess Manimekhalai.