Ponnar and Shankar, who became rulers of Ponni[disambiguation needed] Valanadu in medieval Tamil Nadu, India, were twin sons of a Kongu Vellalar couple named Kundrudaiya Goundar-Thamarai naachiyaar. He is called as Nellian Kodan or Kunnudaiyaan. They are credited with saving their people from an invasion and also gave good style of agriculture with the resources they have. They reminded to thank god and natural resources in every terms of life. They have the habit of affectionate towards their cattle and farms. They married their cousins later.
The legendary story of these brothers, known as Annamar Swamigal. Many families following them used to Name their kids. Annanmaar swamigal folk tales carried out for many generations through village songs, known in Tamil as gramiya padalgal and traditional street theater, known as Therukkoothu. and This story also become the foundation for poems, songs, a film,. Although there is no official geographic area called Kongu Nadu at present, it covers the districts of Coimbatore, Karur, Erode, Salem, Tirupur, Namakkal, Dindigul, Dharmapuri, Krishnagiri and Nilgiris in Tamil Nadu, India 
- "Ponnar-Sankar shooting begins". The Hindu (Chennai, India). 2009-07-13. Retrieved 2009-10-09.
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- K. Chellappan, "Editor's Note," in Kumar, Prema Nanda (1995). Dakshina: a literary digest of south indian languages, 1986-1988. Sahitya Akademi. pp. 231–37. ISBN 978-81-7201-733-0. p. 232.
- "KMK seeks ban on Ponnar Sankar". The Hindu (Chennai, India). 2011-03-25.
- In South, films about politics, by politicians - Indian Express
- "KMK leader criticises film based on CM's novel - Times Of India". The Times Of India. 2011-03-24.