 These four sampradayas emerged in early centuries of the 2nd millennium CE, by the 14th century, influencing and sanctioning the Bhakti movement.The philosophical systems of Vaishnava sampradayas range from theistic Dvaita of Madhvacharya, to qualified monistic Vishishtadvaita of Ramanuja, to pure nondualistic Shuddhadvaita of Vallabhacharya.They all revere an avatar of Vishnu, but have varying theories on the relationship between the soul (jiva) and Brahman, on the nature of changing and unchanging reality, methods of worship, as well as on spiritual liberation for the householder stage of life versus sannyasa (renunciation) stage.