Why do we say that the history of Tamil Nadu goes back to ancient times?

By 300 BC, Tamil Nadu was ruled by three major dynasties – the Cholas, the Pandyas, and the Cheras. This was the classical period of Tamil literature – the Sangam Age – that continued until around AD 300.The Pallava dynasty rose to power in the 7th and 8th centuries. In the 13th century, with threats of Muslim invasions from the north, the southern Hindu dynasties came together to form the empire of Vijayanagar, which covered all of South India. However, by the 17th century, the Vijayanagar Empire broke up. In 1640, the British negotiated the use of Madraspatnam – now known as Chennai as a trading post. After independence, the Madras Presidency was disbanded, and Tamil Nadu was established as an autonomous state in 1956.