The oldest known script in the Indian subcontinent is the undeciphered Harappan script. The oldest deciphered script is Brahmi, dating to around 4th century BCE. In South India, the oldest deciphered script is Tamil-Brahmi which is dated to two centuries after Brahmi. Inscriptions in rock shelters and caves near Madurai provide proof for this.
In an excavation at Kodumanal, near Erode more than 20 pot-sherds with Tamil-Brahmi inscriptions were found. On the basis of this archaeological work, some scholars suggested an older date for Tamil-Brahmi which would put it in the same period as Brahmi. Now there is new evidence from Palani which suggests 400 BCE as the date for Tamil-Brahmi. This adds a new data point to the debate on if Tamil-Brahmi is pre or post-Asokan.
When K. Rajan, Professor, Department of History, Pondicherry University, excavated this megalithic grave, little did he realise that the paddy found in the four-legged jar would be instrumental in reviving the debate on the origin of the Tamil-Brahmi script. Accelerator mass spectrometry (AMS) dating of the paddy done by Beta Analysis Inc., Miami, U.S.A, assigned the paddy to 490 BCE. “Since all the goods kept in the grave including the paddy and the ring-stands with the Tamil-Brahmi script are single-time deposits, the date given to the paddy is applicable to the Tamil-Brahmi script also,” said Dr. Rajan. So the date of evolution of Tamil-Brahmi could be pushed 200 years before Asoka, he argued.[Palani excavation triggers fresh debate via @amargov]
Read the article for it explains the controversies regarding this dating.
Upinder Singh, A History of Ancient and Early Medieval India: From the Stone Age to the 12th Century, 1st ed. (Prentice Hall, 2009).
Recently on the ancient trade path from Madurai to Kerala, archaeologists discovered pottery with Tamil-Brahmi inscription.
Epigraphists have deciphered the three Tamil-Brahmi letters on the ring-stand as “vayra,” which means diamond. The deep-set cist-burial, which has two compartments made of granite slabs, was found to have skeletal remains. A pair of stirrups lay next to the ring-stand. The symbol that followed the three Tamil-Brahmi letters showed an etched gem and bead, with a thread coming out of the bead. According to Mr. Mahadevan, the script could be dated to the first century A.D. [The Hindu : Front Page : Tamil-Brahmi script found in village]
Finding this inscription has been rather lucky because quarrying and vandalism has been destroying Tamil-Brahmi sites.
Tiruvadavur is now the most disturbed Tamil-Brahmi site in the State, with a huge quarry situated right at the foot of the hill. Quarrying has progressed so deep that the site looks like an open-cast mine. All round the quarry, for several kilometres, granite blocks as big as a truck or a car, are stacked on either side of the village roads. There is a surreal scene too: a nearby hill has been sliced in half, as if it were a cake. An official of the State Archaeology Department admitted that quarrying was under way within the prohibited/regulated area, that is, within 300 m of the protected limits of the monument.[History vandalised]
So why is Tamil-Brahmi so important?
Tamil-Brahmi inscriptions are important not only in the history of Tamil Nadu and the rest of South India but for the whole country. They have many unique distinctions. They are the oldest writings in any Dravidian language. They are also the oldest Jaina inscriptions in India. I believe that the Mankulam Tamil-Brahmi inscription of [Pandyan king] Nedunchezhiyan is older than the Karavela inscription at Udayagiri in Orissa.
Tamil-Brahmi inscriptions are the only record of the old Tamil, the one prior to Sangam poetry. Many Tamil-Brahmi inscriptions are important landmarks in our history. For example, the inscriptions of Nedunchezhiyan at Mankulam, the Irumporai inscriptions at Pugalur near Karur and the Jambai inscription of Adhiyaman Neduman Anji link the Sangam age with the Tamil-Brahmi age. It is the Jambai inscription that prove that the “Satyaputo” mentioned by Asoka was none other than the Adhiyaman dynasty, which ruled from Tagadur, modern Dharmapuri.[‘Tamil-Brahmi inscriptions are the only record of old Tamil’]