Copper was the first known metal to man. In North India, the Copper Age followed the Stone Age. In the South, iron was discovered and used by man. Iron implements have been found along with stone implements in Perumbhudhur near Chennai so, it may be said that the Iron Age followed the Stone Age in Tamil Nadu.
During the Metal Age, agriculture had improved much, iron implements were efficiently used for cultivation Paddy was extensively cultivated Later, irrigation System had also improved there was a general progress and development in the life of the people during the Metal Age.
The word megalith refers 10 the burial monument. The people who lived during the last stages of the New Stone Age began to follow the megalithic system of burial, According to this system, the dead body was put in a black and red pot along with iron implements and the pot was buried. A circular tomb using big stone slabs was built upon the place of burial. This is called megalith. Such megaliths have been found in the districts of Kanchipuram, Vellore, Thiruvannamalai , Cuddalore, Tiruchirappalli and Pudukottai.
Another system of burial was known as urn burials. Urns without circular megalithic tombs have been discovered at Adhichanallur in Tirunelveli district. Bronze articles and iron implements are found in these urns. The discovery of trident or Vel in some of these urns suggests that these people worshipped Lord Muruga, the famous God of the Tamil people.
Several utensils made of bronze have been found in Adhichanallur. The hook or alagu, which is still used in religious ceremonies, has been found here. Hence, it may he said that the use of hooks in religious ceremonies was prevalent right from the megalithic period.