Itihasa consists of the Mahabharata and the Ramayana (sometimes the Puranas too, are included). The Mahabharata includes the story of the Kurukshetra War and also preserves the traditions of the lunar dynasty in the form of embedded tales. The Puranas narrate the universal history as perceived by the Hindus – cosmogony, myth, legend and history. The Ramayana contains the story of Rama and incidentally relates the legends of the solar dynasty. The classical Indian poets usually derive the story of their poetry and drama from the Itihasas. In our time, these traditions have been most carefully reconstructed from the available texts and arranged in chronological order by F. E. Pargiter in his compendium Ancient Indian Historical Tradition.
According to the Vedic traditions, human history proceeds in cycles, dependent on the evolutions and dissolutions of the world. Time is divided into four ages – Krita Yuga, Treta Yuga, Dvapara Yuga and Kali Yuga – collectively forming one Maha Yuga. Seventy-one Mahayugas form a Manvantara, a period of time over which a Manu presides. In each cycle, this Manu is the first man and also the first king and lawgiver. Every Manvantara has its own set of Indra, gods and seven sages. Fourteen Manvantara create a Kalpa (aeon), after which the creation comes to a close in a periodical destruction called Pralaya. After that, the creation starts all over again in an endless cycle of evolutions and dissolutions.
The traditions relate that the present Kalpa is called Varaha. Out of the fourteen manvantaras of this Kalpa, six have passed. The current Manvantara is called Vaivasvata after the Manu who presides over it. It is to Vaivasvata Manu that the royal genealogies of the itihasa trace their origin. It was in the Caksusa manvantara, which immediately preceded the present manvantara, that king Prithu, the great grandson of Caksusa Manu, leveled the earth, built cities and villages and developed agriculture, trade, pasture and cattle-breeding. This cycle ended after only eight more generations with the great Flood.