Dandekar theory :

In Dandekar theory, Vaishnavism emerged at the end of the Vedic period, closely before the second urbanisation of northern India, in the 7th to 4th century BCE. Early writings in Dravidian culture such as Manimekalai and the Cilappatikaram present Krishna, his brother, and favourite female companions in the similar terms. Vaishnavism flourished in predominantly Shaivite South India during the seventh to tenth centuries CE with the twelve Alvars, saints who spread the sect to the common people with their devotional hymns. The Bhakti movement of late medieval Hinduism started in the 7th-century, but rapidly expanded after the 12th-century This period saw the growth of Vashnavism Sampradayas (denominations or communities) under the influence of scholars such as Ramanujacharya, Madhvacharya, Nimbarkacharyaand Vallabhacharya. Ramanuja in the 11th century and Madhva in the 13th, building their theology on the devotional tradition of the Alvars (Shri Vaishnavas). In North and Eastern India, Krishnaism gave rise to various late Medieval movements: Nimbarka and Ramananda - 14th century, Kabir and Sankaradeva - 15th and Vallabha and Caitanya - 16th century. All of the Vaishnava Upanishads either directly reference and quote from the ancient Principal Upanishads or incorporate some ideas found in them; most cited texts include the Brihadaranyaka Upanishad, Chandogya Upanishad, Katha Upanishad, Isha Upanishad, Mundaka Upanishad, Taittiriya Upanishad and others The Pancaratra texts present the Vyuhas theory of avatars to explain how the absolute reality (Brahman) manifests into material form of ever changing reality (Vishnu avatar). Vasudeva, state the Pancaratra texts, goes through a series of emanations, where new avatars of him appear. This theory of avatar formation syncretically integrates the theories of evolution of matter and life developed by the Samkhya school of Hindu philosophy In the Varkari movement the following scriptures are considered sacred in addition to general body of the common writing: [citation needed] • Dyaneshawri • Tukaram-Gatha • Sopandevi • Namdev-Gatha • Eknathi-Bhagwat The Bhakti movement originated among Vaishnavas of South India during the 7th-century CE, spread northwards from Tamil Nadu through Karnataka and Maharashtra towards the end of 13th-century, and gained wide acceptance by the fifteenth-century throughout India during an era of political uncertainty and Hindu-Islam conflicts. Important sites of pilgrimage for Vaishnavs include Guruvayur Temple, Sri Rangam, Vrindavan, Mathura, Ayodhya, Tirupati, Pandharpur (Vitthal), Puri (Jaggannath), Nira Narsingpur (Narasimha), Mayapur, Nathdwara and Dwarka. The Vaishnavism traditions may be grouped within four sampradayas, each exemplified by a specific Vedic personality. They have been associated with a specific founder, providing the following scheme: Brahma Sampradaya (Madhvacharya), Sri Sampradaya (Ramanuja), Rudra Sampradaya (Vishnuswami, Vallabhacharya), Kumaras sampradaya (Nimbarka) The Alvars, "those immersed in god," were ten or twelve Tamil poet-saints of South India who espoused bhakti (devotion) to the Hindugod Vishnu or his avatar Krishna in their songs of longing, ecstasy and service. The Alvars appeared between the 5th century to the 10th century CE, though the Vaishnava tradition regards the Alvars to have lived between 4200 BCE - 2700 BCE.