Edgar Thurston (Castes and Tribes of India Volume 5) states that the Kongu region was ruled by a series of twenty eight kings before being conquered by the Cholas of Tanjore, citing the earliest portion of the Kongu Chronicle - "Kongu Desa Rajakkal" (a manuscript in "The Mackenzie Collection") which gives a series of short notices of the reigns of all the kings who ruled the country from the start of the Christian era till its conquest by the Cholas. These kings belonged to two distinct dynasties: the earlier line of the "Solar race" which had a succession of seven kings of the Ratti tribe, and the later line of the Ganga race, itself claimed to be a branch of the Solar race.