The Alwars (also spelled Azhwars) are a group of 12 ancient Vaishnava saints who lived in Tamil Nadu and are famous for their devotional poetry in praise of Vishnu. The collection of their 4000 poems, known as the Naalayira Divya Prabhandam, is considered by many to be the "Dravida Veda", or South Indian Veda. The Alwars are crucially important figures in the history of Vaishnavism; it's the beliefs and principles embodied in the Alwars' poems that ultimately gave rise to the Sri Vaishnava sect (of which I'm a member).
One of the Alwars was known as Thirumazhisai Alwar. He was the son of the sage Bhargava, but he was raised by tribal people and became a famous Shaivite poet, before ultimately converting to Vaishnavism. And as I discuss in this question, he is said to have been born in the Dwapara Yuga, almost a thousand years before the birth of Krishna! In any case, this article from the Hindu makes an interesting claim about Thirumazhisai Alwar:
This Azhwar is, perhaps, the most controversial in the hierarchy as he is supposed to have lived in the Dvapara Yuga. Tamil scholars have, however, placed him in the sixth or seventh century A.D. as the Azhwar was a contemporary of a Pallava ruler of Kanchipuram. After critically studying all systems of philosophy like Jainism, Buddhism, Mayavada and Saivism, he became a staunch follower of Vaishnavism. A renowned Sanskrit scholar has identified this Azhwar as Dramidacharya referred to by Ramanuja and has furnished convincing evidence for his conclusion.
My question, who is this "renowned Sanskrit scholar" who said that Dramidacharya is the same as Thirumazhisai Alwar? For those who don't know, Dramidacharya, aka Dravidacharya, was a famous pre-Shankara Vedantic philosopher whose works are now lost, but quotes from his works survive in other people's works. In Ramanujacharya's works he is reverentially spoken of as the Bhashyakara. He wrote a commentary on the Chandogya Upanishad, and probably a commentary on the Brahma Sutras as well. He may be the Bhashyakara spoken of in this quote from Yamunacharya's Atma Siddhi:
For the sake of this objective, the Sutras were written by Bhagavat Badarayana; they were then explained by the author of the bhashya, which expressed tersely their profound meaning; this was explained in detail by Bhagavat Srivatsankamishra who declared the truth profound as an ocean.
The philosophical approach herein is one that has been presented by the Vedas, whose import has been clearly revealed by the ancient commentaries on the Vedas and Vedanta and has been unanimously adopted by the great ones like Bhagavan Bodhayana, Tanka, Dramida, Guhadeva, Kapardin and Bharuchi. By this, the extra-Vedic schools of thought like those of Charvaka, Shakya, Aulukya, Akshapada, Kshapanaka, Kapila and Patanjali along with the schools of some followers of the Vedas whose vision is been perverted, are refuted.
Dramidacharya is also quoted by Adi Shankaracharya in his commentary on the Chandogya Upanishad, and may be quoted in his Brahma Sutra Bhashya as well (as discussed in my question here.)
In any case, who is the Sanskrit scholar who identified Dramidacharya with Thirumazhisai Alwar, and what is the "convincing evidence" that he provided for it? One thing is that the name Dramida or Dravida meana "South Indian", so it would be a fitting name for a Tamil poet like Thirumazhisai Alwar. Another thing is that Dramidacharya discusses the steps of Bhakti Yoga, as I discuss in this answer. So that would be consistent with Thirumazhisai Alwar's Bhakti towards Vishnu.
I would try asking the author of the article, but he passed away ten years ago.