"The 18 Mahapuranas (great Puranas), as the origins of the Puranas, may have overlapped to some extent with the Vedas, but their composition stretched forward into the 4th-5th centuries,... the earliest parts of the Puranic genealogies are either entirely or partly w:Mythicalmythical. The oldest of the Puranas are the Matsya, Vayu and the Brahmanda and for our purposes, the Vishnu Purana, somewhat later than the first three … the Vedic link also goes back to the earlier statement that the itihasa-purana was the fifth Veda."