This temple was the abode of Sri Ramanujacharya,who espoused the Qualified Non Dualism, Visishta Advaitha,Visishtadvaida,. He had to flee from the Chola kingdom, Sri Rangam due to persecution from the king and some Vaishnavas and Shaivas. One may add here that there no mention of Shaivas and Vaishnavas in the Vedas, and as such, in my opinion,the difference between them, to say the least,is not what Vedas say.
One is basically a ruse to grab land( Christians and Muslims also indulge in this) by installing an Idol and as the visitors increase a temple /Church/Masjid is built.In the case of Islam,in lieu of Idol a green flag is installed initially. The second one is built by Mutts, Religious Organisations. Some of them are sanctified by Kumbabhisheka performed according to Agamas. These are very few.
Tipu ordered his troops to round up all Mandyam Iyengars of Melkote, many of whom were relatives and friends of Tirumaliyengar, and he massacred them in cold blood. The slaughter was on the day when the Mandyam Iyengars were getting ready to celebrate Naraka Chaturdashi. The celebrations turned into mourning.