Tapasya
This incident made a deep impression on the King. He realized that the power obtained by penances was far greater than mere physical might. He renounced his kingdom and began his quest to become a greater rishi than Vasistha. He took on the name Vishvamitra. It is very interesting to see all the challenges that Viswamitra faced in his life to become a Brahmarishi, before eventually giving up the greed to possess the cow. After many trials and undergoing many austerities, Vishvamitra at last obtained the title of Brahmarishi from Vasistha himself. During this time he had a daughter named Shakuntala (who appears in the Mahabharata) with Menaka, an apsara in the court of Indra. Son of Shakuntala became a great emperor. He came to be known as Emperor Bharata, in whose name the land of India got its name Bharatha.
Read more about this topic: Vishvamitra