CHENNAI: Of the 40 archaeological sites excavated so far in various parts of Tamil Nadu , at least 20 may have existed during the Sangam period."Sites like Kodumanal, Arakkamedu and the recently excavated Keezhadi have cultural links to Pattanam, on the banks of the Periyar river in Kerala. The material evidence shows that Pattanam had connections with 40 port sites from South China to Gibraltar. Maybe for the first time in history, people from different continents such as Asia, Africa and Europe started travelling from port to port during this period," said senior archaeologist P J Cherian, who is director of PAMA, Institute for the Advancement of Trans-disciplinary archaeological sciences in Kerala.Speaking on "Re-imaging Muciri-Pattinam/Muziris: The ancient port city of Tamilakam (300BC-500BC)" recently at the Tamil Virtual Academy, Cherian said he had been trying to rediscover the sites in Tamilakam to understand the cultural significance existed during the Sangam period. It was while heading the Kerala Council for Historical Research in 2007 that a team led by Cherian excavated Pattanam with archaeological evidence that it could be an ancient town which was once part of the port site known as Muziris.Cherian said he could excavate only a minor part of the site in Pattanam. However, the evidence he got from the site showed connections to many Sangam-period sites in Tamil Nadu."Pattanam must have been an integral part of the ancient trading port of Muziris/Muciri Pattinam. As a trans-oceanic hub, the region finds copious mention in various Indian as well as European classical texts. We have received material evidence that Pattanam could have been or was part of Muziris. In Sangam literature , it is mentioned that the Romans used to refer to Muciri Pattanam as Muziris. If that's the case, then Pattanam could have been the Mohenjo-daro of the south India," he said.The ancient regions of today's Tamil Nadu and Kerala had great connections, according to Cherian. "The regions of today's Kerala and Tamil Nadu had great links between Pattanam in Kerala and Kodumanal, Arakadedu and Veerampattinam, Kaveripattinam in Tamil Nadu. See some sites have the names 'Pattanam'. It shows a great coexistence," he said.However, it was not restricted to two or three states. "The exchange of ideas and beliefs crossed the seas, linking to the Romans, Arabians, Christians from across the continents," he said. Cherian said he has got enough material evidence to show that some sites in Tamilakam and Pattanam were prominent sites of coexistence of various cultures and beliefs.