The Shiva Purana is one of the eighteen Purana genre of Sanskrit texts in Hinduism, and part of the Shaivism literature corpus. It primarily centers around the Hindu god Shiva and goddess Parvati, but references and reveres all gods.The Shiva Purana asserts that it once consisted of 100,000 verses set out in twelve samhitas (books). It was written by Romaharshana, a disciple of Vyasa belonging to Suta class. The surviving manuscripts exist in many different versions and content, with one major version with seven books (traced to South India), another with six books, while the third version traced to the medieval Bengal region of the Indian subcontinent with no books but two large sections called Purva-khanda (previous section) and Uttara-khanda (later section). The two versions that include books, title some of the books same and others differently. The Shiva Purana, like other Puranas in Hindu literature, was likely a living text, which was routinely edited, recast and revised over a long period of time. The oldest manuscript of surviving texts was likely composed, estimates Klaus Klostermaier, around 4th to 2nd century BCE. Some chapters of currently surviving Shiva Purana manuscripts were likely composed after the 1st century CE.The Shiva Purana contains chapters with cosmology, mythology, relationship between gods, ethics, Yoga, Tirtha (pilgrimage) sites, bhakti, rivers and geography, and other topics. The text is an important source of historic information on different types and theology behind Shaivism in early 1st-millennium BCE. The oldest surviving chapters of the Shiva Purana have significant Advaita Vedanta philosophy, which is mixed in with theistic elements of bhakti.