The first is related by the sage Pulastya to Bhisma (Part 1: chapter 30), which took place 'formerly in the Satya Yuga'. Similar to the legend of Vritra in the Bhagavata Purana, Baskali (i.e. Bali) conquers the gods led by Indra after attaining the boon of invincibility from Brahma, forcing them to ultimately seek Vishnu for refuge. Vishnu agrees to help, and Aditi (wife of Kasyapa) is pregnant for 1,000 divine years with the Vamana avatar. It is noted that Aditi 'entertained a malicious design' to destroy the demons during her pregnancy.