Let us see how the date of tamil language is advanced
Date of Silapathikaram
Gajabahu synchronism is the chronological device used by historians to help date tamil literature. From a mention in the silapathikaram, the Lanka king Gajabahu is taken to be a contemporary of the cheran king senguttuvan
"The monarch of the world circumambulated the shrine thrice and stood there proferring his respects. In front of him the Arya kings released from prison, kings removed from central jail, the Kongu ruler of Kudagu, the king of Malva and Kayavaku, the king of sea-girt Ceylon, prayed reverently to the deity thus.."
Kayavaku here, despite disagreement has been taken to mean Gajabahu. According to the Mahavamsa , Gajabahu I reigned between 113 - 134 CE, while Gajabahu II reigned in the 12th century CE. This, in turn, has been used to imply that the Chera king, who according to the pathirupattu ruled for 55 years may be dated to c. 110 - 165 CE. This computation, which was first proposed by V Kanakasabhai Pillai in his book, The Tamils 1800 years ago (1904), has come to be known as the Gajabahu synchronism. Kanakasabhai also mentions another reference from Silappatikaram which has the Chera king meet the Magadha king Nurruvan Kannar who is interpretted to as satkarni, satvahana dynasties as an additional proof for the synchronism.
Kanakasabhai's reasoning for not considering Gajabahu I as the king mentioned is as follows:
“ In the long list of kings of Ceylon preserved in Singhalese chronicles, the name Gajabahu occurs only twice. Gajabahu I lived in the early part of the second century A.D. and Gajabahu II in the twelfth century. If the latter was king referred to in the Cilappathikaram, Karikala Chola, the grandfather of the Gajabahu contemporary, Imaya Varamban should have lived in the eleventh or twelfth century A.D. But in many Tamil poems and inscriptions on copper plates recording the grants of Chola kings who lived in the tenth and the eleventh centuries, Karikala Chola I is described as one of the earliest and most remote ancestors of the Chola kings then reigning. It is evident therefore that the Gajabahu referred to in the Cilappathikaram could not be Gajabahu II, but must have been Gajabahu I, who was king of Ceylon from about A.D. 113 to A.D. 125."
However Many contentious points remain
1. How come Kayavaku becomes GajaBahu
2. How come Nurruvan Kannar becomes Satkarni
3. Gajabahu is dated by Mahavamsa at 110 to 165AD , But satkarni is not the same period how come they have come and attended a ceremony.
4. How come there is no other citation of Satkarni attending the ceremony.
5. A king of malwa attending the ceremony should be great news , how come it goes with just reference.
6. There is no reference of of Gajabahu ever coming to Kerala both in Mahavamsa and others.
Not just this there is no evidence of author Ilanko adigal ever lived as witness, he does not have any evidence to show that he was a eyewitness. As he never goes into details. The king senguttuvan is said to have taken a great expedition and conquered himalayas , that also we dont have any proof.
Since karikalan cannot be dated to 12th century does not mean he has to be dated to 2nd century , he might well be 9th century or 10th century AD.
So the whole Gajabahu synchronization falls flat on the face.
That is used to justify the antiquity of tamil literature is a really not going with facts.