On the pretext of a great bow festival, Kansa sent Akrura to bring Krishna and Balarama to Mathura. As they left Braj, the hearts of the gopis and Mother Yashoda overflowed with grief. That longing of separation is still sung in countless bhajans today.
As soon as they entered Mathura, Kansa's elephant Kuvalayapida was set loose upon them, and Krishna brought it down. Then in the wrestling arena they defeated mighty wrestlers such as Chanura and Mushtika. Finally Shri Krishna pulled Kansa down from his throne, slew him and freed Mathura from tyranny.
He freed his mother Devaki and father Vasudeva from prison and returned the throne to Ugrasena, Kansa's father. Though he was God himself, he chose not to become king.
After this, Krishna and Balarama went to study at the ashram of Sage Sandipani in Ujjain. It was there that his everlasting friendship with Sudama, a poor Brahmin boy, began. As his offering to his teacher, Shri Krishna brought back the guru's son, who had drowned in the sea.