According Vishnu Purana and Bhavishya Purana the name “Mithila” is derived from King Mithi, who established the city of Mithilapuri.[2] He was also known as Janaka because he was born out of the body of his father. The title Janaka was later adopted by subsequent kings of Mithila.[3][4] According to Bal KandofValmikiRamayana, King Mithi had a son named as Udavasu who became successor of the kingdom after him.[5]
According to the sixth chapter of Devi Bhagavata, once the King Nimi was cursed to death by the sage Vashishtha for performing Yajna in his absence. Then the other sages present there took the lifeless body of Nimi and after performing Yajna rituals and worshipping the gods, they started churning the body. After some time, a great, radiant, powerful and accomplished man was born from it. Since he was born by Mathana (churning) he was named Mithi.[6]