 There are no references to Thanjavur in any of the Sangam period ( third century BC to fourth century AD ) Tamil records , though some scholars believe that the city has existed since that time . Kovil Venni , situated 15 miles ( 24 km ) to the east of the city , was the site of the Battle of Venni between the Chola king Karikala and a confederacy of the Cheras and the Pandyas . The Cholas seemed to have faced an invasion of the Kalabhras in the third century AD after which the kingdom faded into obscurity . The region around present day Thanjavur was conquered by the Mutharayars during sixth century , who ruled it up to 849 . 
