 Ecstatic with her blessings , Satyavati gave birth the same day to her baby on an island in the Yamuna . The son immediately grew up as a youth and promised his mother that he would come to her aid every time she called on him ; he then left to do penance in the forest . The son was called Krishna ( " the dark one " ) due to his colour , or <unk> ( " one born on an island " ) and would later become known as Vyasa – compiler of the Vedas and author of the Puranas and the Mahabharata , fulfilling Parashara 's prophecy . After this , Satyavati returned home to help her father . 
