The history of Ranganatha (Vishnu) temple of Tamil Nadu is situated on the island of Srirangam near Tiruchirapalli. The Koil Olugu is an elaborated work written in Tamil, which tells about the complete history of this temple.

The Koil Olugu describes the contributions of the Alvars and the Acharyas and the kings of the different dynasties like the Cholas, Pandyas and the Vijayanagar emperors and their successors to this temple. The description given here are very helpful for the historians, who want to know about the political, social and cultural history of this area and of South India as a whole in the ancient and medieval periods.

The most important facts written here include the portrayal of the different shrines in this vast temple complex and the kings and ministers who either built them or decorated them. This Koil Olugu explains about the Muslim rulers, who invaded this temple town and destructed the beauty and charm of it. These writings also tell about how the establishment of the mighty Vijaya-nagara Empire on the banks of the river Tunga-badhrain 1336 A.D. brought a turning point in the history of South India.

The Koil Olugu informs that the Muslim invasions in South India were stopped by the Vijayanagara rulers when they came into the throne. The Vijayanagara rulers also started rebuilding and reconstruction of the temples of South India, which were demolished by the Muslims in their earlier invasions.

From this Koil Olugu, it is also known that the kings of the Vijayanagara dynasty reconstructed various shrines in the temple-city of Srirangam. The genuineness of all these facts are proved by the inscriptional evidence found at this temple with regard to the dates and the names of dynasties and kings.