Purana (पुराण) - Ancient Scriptures pertaining to Hinduism

The Puranas (Vishnu Puran, Shiv Puran and Brahma Puran) sing the glory of Brahm (Kaal) who is the father of Brahma, Vishnu and Shiva. He is therefore addressed as Mahavishnu, Mahabrahma or Mahashiva (Sadashiv). 

All the Puranas were compiled by Sage Ved Vyasa. 

Brahma was the first recipient of Vedas after the churning of the ocean. Brahma read the vedas and gave the knowledge to his descendants. Descendants of Brahma are various rishis (sages). The tales and stories told by Brahma after reading the vedas to his descendants formulated the content of the Puranas. This is the reason Puranas are below the Vedas and the Bhagavad Gita in the hierarchy of holy scriptures pertaining to Hinduism with the vedas being at the summit.