Kalyani, It is Kovalan and not Kovala. The epic is called "Silapadhikaram" in Tamil and it was written by Elangovadigal.Kannagi is regarded with high respect in Tamilnadu.There is one statue for Kannagi near the Marina Beach in Chennai and the busstop is named "Kannagi Silai".Silai means statue. The story has one more character named Madhavi. I have read this story in school days.I don't remember much of this. Whatever i remember i have written below.
Kovalan and Kannagi are happy couples.At one stage,Kovalan watches the dance of Madhavi and getting attracted to her.He tooks the Silambu (ornament weared in foot) of Kannagi and tries to sell it. Pandiyan king captures Kovalan and says that the silambu belongs to his wife and he had stealed. So he killed him for his crime.On hearing this news, Kannaga enters the kingdom and says that her husband can never be a thief.She says her silambu is composed of Manickam ( A stone ) whereas the silambu of King's wife is made of Pearl. She breaks her silambu and Manickam comes out of that.She curses that the kingdom will be destroyed as if failed to give the correct judegement and punished an innocent man. Her curse destroys the whole kingdoam and the king also dies as he had given wrong judgement.
These events happened in a place called Madurai in Tamilnadu.