Purusha (Sanskrit पुरुष) is a complex concept whose meaning evolved in Vedic and Upanishadic times. Depending on source and historical timeline, it means the cosmic being or self, consciousness, and universal principle. Author Steven Rosen says, The Bhagavata Purana and the Mahabharata boldly proclaim Vishnu as ultimate Purusha described in Purusha Sukta prayer. According to Indologist W. Norman Brown, The verses of Purusha Sukta are definitely a reference to Vishnu, who, through his three steps, is all pervading (i.e. he spreads in all directions).