What is "manatunga"

Acharya Manatunga (c. seventh century CE) was the composer of famous Jain prayer, Bhaktamara Stotra. Acharya Manatunga is said to have composed the Bhaktamara Stotra when he was ordered to be kept in prison for not obeying the orders of King Bhoja to appear in his royal court. He was kept in the prison tied up under chains and 48 locks, and upon chanting the Bhaktamara Stotra all the 48 locks were broken and Acharya Manatunga miraculously came out of the prison.