Ashmaka was born to Vasishta and the wife of Kanmashapada, king of Ayodhya.

The king once reached Vasishta’s ashram during a hunt. At that time, Vasishta’s son Shakti, eldest among hundred sons, came by, but refused to give way to the king. The furious king whipped Shakti, who in turn, cursed the king and made him a rakshasa. The rakshasa immediately killed Shakti. After several years, Vasishta lifted the curse and a grateful Kanmashapada took him to his palace. As per the king’s instructions, his wife Madayanti slept with Vasishta, to get a son. Soon she became pregnant and Vasishta  returned to the forests. But even after several years, Madayanti failed to give birth. Finally she was so frustrated that she beat her swollen belly with a grinding stone’s cylindrical part (ashma) and Ashmaka was born. Ashmaka built a city called Paudhanya as per Mahabharata Adiparva Chapter 176.