Balarama, strength of Rama, is an incarnation of Vishnu. Mentioned in Hindu Epic and Puranic literature, the deity may have originated in Vedic times as an agricultural fertility god. He is the son of Vasudeva and Devaki, though from the womb of Rohini. Jointly with Krishna, his brother, he is identified as the eighth avatar of Vishnu, or, with Rama, the seventh. According to legend, Vishnu impregnated the belly of the goddess Devaki with two hairs, one black, one white. To ensure their safety against a demon king, they were transferred before birth into Rohini. Krishna grew to be dark skinned, and Balarame light. Although Balarama shared the same characteristics as his brother, he was not as popular as Krishna. He is usually depicted as standing to the right of Krishna, and rarely standing alone. His consort is Revati, and his sons are Nisatha and Ulmuka. Among his epithets is Ananda (Joy).
Jordan, Michael, Encyclopedia of Gods, New York, Facts On File, Inc. 1993, p. 39