A striking Nataraja (Rudra Thadava) on the Walls of the Vishnu Temple (Run by Iyengars) at Tirukurungudi near Tirunelveli:
Tirukurungudi near Tirunelveli is a Vaishnavite Temple. But Shree Vaishnavism is a young religion while many of the temples it took over, including Tirupathi are far older, as this Rudra Thandava (Nataraja) on the wall of Tirukurungudi testifies.
Many of the Great Vaishnavite Temples of the South were earlier Subrahmanya Temples. The left hand of Tirupathi Venkataramana, for example, still supports the now missing spear. The idol is not “Chathurbhuja” as one might expect of a Maha Vishnu idol, Azhagar Koil, near Madurai, presided over by Panchayudha Vishnu with a very powerful Sudarshana Narasimha shrine at its Nairuruthi, and a key player in the Chitrai festival where Azhagar goes to Madurai to give his sister Meenakshi in marriage to Sundareshwara, was earlier the Pazharmuthirsholai Subrahmanya Temple
The Iyengars adopted Ganapathi into their pantheon as “Thumbikai Alvar” (Elephant Trunked Devotee of Vishnu) because of the myth that Ganapathi in the form of a Brahmin fooled Vibhishana (at Srirangam) and Ravana (at Gokarna) to give him Vishnu’s Vaikunta Saligrama and Shiva’s Atma Linga respectively to hold so that they could relieve themselves of the waters that Varuna had filled their bladders with, and then put them down so that they could not be moved again.
But Valmiki’s Ramayana does not mention these tales or mention Ganapati at all for he was a tribal deity and not in the Aryan Pantheon during the Ramayana nor in the Druido Aryan Pantheon (of the Atharva Veda period) and was included in the Panchayathana by Adi Shankaracharya who composed the Atharva Sheersha and Namavali for him. It might have also come to pass as many of the Thengalai Iyengars were converted tribals and ubiquitous Ganapathi might have been too difficult to erase from all the temples that they converted to Shree Vaishnavism and the Vaikanasa Sutra.
In the initial stage of the founding of Shree Vaishnaivism, they were aggressive and started converting major centers of pilgrimage to Shree Vaishnavism AND worship as per the Vaikanasa Sutra. They were able to get the support of the local congregations by offering bilingual formula for all rituals. i.e. they performed their worship in BOTH Sanskrit and Tamil. Subrahmanya temples were particularly vulnerable as the Pandyas who once ruled almost all of South India and had trading posts all the way to Rome in the West and through out South East Asia had perpetuated the myth that Subrahmanya, their patron deity, was the originator of Tamil.
Time lines in those days are very difficult to establish. However, an attempt can be made. Ramanujacharya who personally took Tirupathi from Subrahmanya was forced into self exile at Melkote, where the Nachiyar episode is supposed to have happened, by Kulothunga Chola who applied lawful pressure on Shree Vaishnavites to desist from putting their Namam Symbol on Shiva idols. this was some eight hundred years ago (1100 CE?). As the Bahmanis (Gulbarga, Bidar and then Hyderabad) a branch of the Ottoman (Turkic) Caliphate (1347 CE (?) onwards) had not reached the South during Ramanuja’s time, it is likely that the story of Nachiyar was created to help in a belief structure that would permit the reintegration (Ghar Wapasi) of Kidnapped, Raped and Fallen women. Vijayanagar was established to counter the Moslem raiders on the orders of Vidya Aranya Mahaswamnaha of Shringeri around 1300 CE.