Vaishnavas affirm Vishnu, and his avatars, above all Krishna and Rama, as the supreme deity, the source and sustainer of all, from whom the other gods derive. On this view the ultimate reality is a personal, gracious Lord who descends into the world in successive incarnations (avataras) to restore righteousness whenever it declines, as the Bhagavad Gita has Krishna declare. Salvation comes chiefly through bhakti, loving devotion and surrender to the Lord, who receives the devotee by grace.
Vaishnava theology is itself divided among several major lineages (sampradayas), each with its own philosophical school: the Sri Vaishnavas, following Ramanuja's eleventh-century qualified non-dualism (Vishishtadvaita); the Madhva or Brahma sampradaya, holding Madhva's thirteenth-century strict dualism (Dvaita), on which the soul and God remain eternally distinct even in liberation; and the Gaudiya Vaishnavas, founded on the ecstatic devotionalism of the Bengali saint Chaitanya (1486 to 1534), whose tradition of congregational chanting (kirtan) of Krishna's names underlies the modern International Society for Krishna Consciousness, founded by A. C. Bhaktivedanta Swami Prabhupada in 1966.