Mahavamsa has a very negative reputation among Tamils due to its apparent political bias. For example, Mahavamsa describes the 44-year reign of Elara, a righteous Tamil king who patronized Buddhism despite being a non-Buddhist in 21 stanzas. However, Dutugemunu's 24-year rule is described in 843 stanzas (chapters 21-30). The Mahavamsa mindset also contributed to the rise of anti-Tamil nationalism in Sri Lanka. A number of scholars, including some prominent Sinhala historians, have written extensively about the Mahavamsa mindset's role in racial tensions.
But only a few Tamils know that Mahavamsa (5th century AD Pali text) once played a big role in dating ancient Tamil literature. In the past, Western scholars believed Tamil's oldest books were written around the 8th century. Due to the linguistic sophistication and maturity of early Tamil texts, they disagree with most Tamil scholars that early Tamil literature could date back before Christ. The locations or events described in old Tamil literature had no archaeological evidence (a lot has been discovered since 1960). They were about to change their minds in 1904.
A Sri Lankan Tamil scholar named Kanakasabhai noticed something significant in 1904 while reading the ancient Tamil epic "Silappatikaram" (5,730 line poem). Sri Lankan King Gajabahu was present at Chera king Senguttuvan's court when Senguttuvan consecrated a temple for Kannagi (Pattiṉi Deviyō in Sinhala). He immediately turned to the Mahavamsa's records. The Mahavamsa mentions two Gajabahus. Gajabahu I reigned between 113 and 134 CE, and Gajabahu II reigned in the 12th century. Since the Tamil country had been united under the Imperial Chola empire during Gajabahu II's time, the Chera dynasty was not in power. This led Kanakasabhai to conclude it was Gajabahu I.
Consequently, the author of "Silappatikaram", who was also the brother of Senguttuvan, belongs to the same period as Gajabahu I. Due to the fact that "Silappatikaram" was read out at Chera court, it can be assumed that it was written around 120 AD. This method is now known as "Gajabahu synchronism". Using this date as a reference, he dated the remaining Tamil texts that pre-date Silappatikaram. Based on various linguistic comparisons, he determined that "Tholkaappiyam", the oldest surviving Tamil book, was written around 300 BCE or earlier. During the late 20th century, archaeological discoveries proved his dates were correct.
Kanakasabhai's discovery was instrumental in starting the debate which led to the world's recognition of Tamil as a classical language. A UNESCO report in 1984 noted, "Tamil culture is remarkable on many counts, not least because Tamil is the oldest of India's modern languages. Tamil is perhaps the only example of an ancient classical tongue that has survived for more than 2,500 years with its basic structure intact." If we had waited for archaeological discoveries to emerge in the 1960s, Tamil's place as a classical language would have remained under scrutiny today.
Modern Tamil society was also profoundly impacted by Kanakasabhai's discovery. It was Kanakasabhai's discovery that provided the momentum for the Tamil linguistic purity movement. At that time, Sanskrit loan words heavily influenced Tamil. Tamils understood the need to protect Tamil in its purest form when definitive proof of Tamil's antiquity became evident. A direct result of the Tamil language purity movement is the Tamil we speak today, with few loan words from other languages. So there are both positive and negative influences on Tamil lives due to Mahavamsa.