The three chiefly lines of the early historic south India – the Cheras, Pandyas and Cholas – were known as the mu-vendar ("the three vendars"). They traditionally based at their original headquarters in the interior Tamil Nadu (Karur, Madurai and Uraiyur respectively). The powerful chiefdoms of the three ventar dominated the political and economic life of early historic south India. The frequent conflicts between the Chera, the Chola and the Pandya are well documented in ancient (the Sangam) Tamil poetry. The Cheras, Cholas and Pandyas also controlled the ports of Muziris (Muchiri), Korkai and Kaveri respectively (for the trade with the Graeco-Roman world). The gradual shift from chiefdoms to kingdoms seems to have occurred in the following period.The famous inscription of king Kharavela at Hathigumpha (mid-first century BCE) mentions the defeat of a confederacy of the "Tramira" countries which had been a threat to Kalinga. It also remembers the precious pearls brought to the capital as booty from the "Pandya" realm. The Pandya chiefdom was famous for its pearl fisheries and silk industry. Korkai and Alagankulam are believed to have been the exchange centres of the Pandyas. Korkai, a port at the mouth of the river Tambraparni, was linked to the famous pearl fisheries and Alagankulam was also developed as a port.