As such, it is a subset of mainstream Indian and Nepali culture. The roots of mythology that evolved from classical Hinduism come from the times of the Vedic civilization, the four Vedas, notably the hymns of the Rigveda, contain allusions to many themes. The characters, philosophy and stories make up ancient Vedic myths are indelibly linked with Hindu beliefs. The Vedas are four in number, namely RigVeda, YajurVeda, SamaVeda, in the period of Classical Sanskrit, much material is preserved in the Sanskrit epics. Besides mythology proper, the voluminous epics also provide a range of information about ancient Nepali and Indian society, philosophy, culture, religion. The two great Hindu Epics, the Ramayana and the Mahabharata tell the story of two incarnations of Vishnu. These two works are known as Itihasa, the epics Mahabharata and Ramayana serve as both religious scriptures and a rich source of philosophy and morality. The most famous of these chapters is the Bhagavad Gita in the Mahabharata, in which Lord Krishna explains the concepts of duty and these stories are deeply embedded in Hindu philosophy and serve as parables and sources of devotion for Hindus. The Mahabharata is the worlds longest epic in verse, running to more than 2,000,000 lines, the epics themselves are set in different Yugas, or periods of time. The Ramayana, written by the Maharshi Valmiki, describes the life and times of Lord Rama, the Mahabharata, describing the life and times of the Pandavas, occurs in the Dvapara Yuga, a period associated with Lord Krishna. In total, there are 4 Yugas and these are the Satya or Krita Yuga, the Treta Yuga, the Dvapara Yuga, and the Kali Yuga. The avatara concept, however, belongs to the Puranic times, the Puranas deal with stories that are old and do not appear in the epics. They contain legends and stories about the origins of the world, and the lives and adventures of a variety of gods, goddesses, heroes, heroines. They contain traditions related to ancient kings, seers, incarnations of God and legends about holy places, the Bhagavata Purana is probably the most read and popular of the Puranas. It chronicles the legends of the god Vishnu and his avatars on earth, the act of creation was thought of in more than one manner. One of the oldest cosmogonic myth in the Rigveda had come into existence as a cosmic egg, the Purusha Sukta narrates that all things were made out of the mangled limbs of Purusha, a magnified non-natural man, who was sacrificed by the gods. In the Puranas, Vishnu, in the shape of a boar, plunged into the cosmic waters, the Shatapatha Brahmana says that in the beginning, Prajapati, the first creator or father of all, was alone in the world. He differentiated himself into two beings, husband and wife, the wife, regarding union with her producer as incest, fled from his embraces assuming various animal disguises
Depictions of episodes from Hindu mythology
Rama (right) seated on the shoulders of Hanuman, battles the demon-king Ravana, scene from Ramayana.
The Creation of the Cosmic Ocean and the Elements, folio from the Shiva Purana, c. 1828.