Vyasa appears for the first time as the compiler of, and an important character in, the Mahabharata. It is said that he was the expansion of the God Vishnu, who came in Dvapara Yuga to make all the Vedic knowledge from oral tradition available in written form. He was the son of Satyavati, adopted daughter of the fisherman Dusharaj and the wandering sage Parashara, who is credited with being the author of the first Purana, Vishnu Purana. He was born on an island in the river Yamuna. Due to his dark complexion, Vyasa was also given the name Krishna, in addition to the name Dwaipayana, meaning island-born.