Tamil Classics also speak of Kanchi,and the Sangam Literature calls it as Kanchi Mudur,Ancient Kanchi.( The Term Mudur is used only for two cities (Mudur),Madurai and Kanchi).
These two cities are quite ancient if one goes through these references.
A Brahmin from Kanchi founded Cambodia Vietnam Thailand
Kanchi tribe is mentioned in the Mahabharata Thus,