Lord Vamana, an incarnation of Lord Krsna, appeared in this world in a previous age, millions of years ago. When He appeared from the womb of Aditi, He was equipped with disc, club, lotus, and conchshell the symbols of Lord Visnu. After His appearance the Lord assumed the form of a dwarf (vamana). Great sages performed rituals for the Lord's birth ceremony, and when the Lord received the sacred thread worn by brahmanas, demigods came from all over the universe to offer Him gifts.
Lord Vamana approached Bali Maharaja with a mission to recover for the demigods the heavenly planets, which Bali had conquered. When Bali Maharaja requested the Lord to ask for something in charity, Lord Vamana said that He would be satisfied with three paces of land, as measured by His own steps. With two steps Lord Vamana covered the entire universe. When the Lord asked Bali where He could put His third step, Bali offered his own head, thus revealing himself to be a surrendered devotee of the Lord. Because of this pastime, Lord Vamana is also know as Trivikrama, "one who took three great steps."