The Alvars () were the Tamil poet-saints of South India who espoused bhakti (devotion) to the Hindu preserver deity Vishnu, in their songs of longing, ecstasy, and service. They are venerated in Vaishnavism, which regards Vishnu as the Ultimate Reality. Many modern academics place the lifetime of the Alvars between the 5th century and 10th century CE. Traditionally, the Alvars are considered to have lived between and . Orthodoxy posits the number of Alvars as ten, though there are other references that include Andal and Madhurakavi Alvar, making the number 12. Andal is the only female Alvar among the 12. Together with the contemporary 63 Shaivite Nayanars, they are among the most important saints from Tamil Nadu. The devotional outpourings of the Alvars, composed during the early medieval period of Tamil history, were the catalysts behind the Bhakti Movement through their hymns of worship to Vishnu and his avatars. They praised the Divya Desams, the 108 divine realms of deities affiliated to Vaishnavism. The poetry of the Alvars echoes bhakti to God through love, and in the ecstasy of such devotions they sang hundreds of songs which embodied both depth of feeling and the felicity of expressions. The collection of their hymns is known as the Naalayira Divya Prabandham. The bhakti literature that sprang from Alvars has contributed to the establishment and sustenance of a culture that deviated from the Vedic religion and rooted itself in devotion as the only path for salvation. In addition, they contributed to Tamil devotional verses independent of a knowledge of Sanskrit. As a part of the legacy of the Alvars, five Vaishnavite philosophical traditions (sampradayas) developed over a period of time. Etymology The word Alvar has traditionally been etymologized as from Tamil. Al (ஆழ்), 'to immerse oneself' as 'one who dives deep into the ocean of the countless attributes of god'. The Indologist Sudalaimuthu Palaniappan has established from epigraphy and textual evidence that the traditional term Āḻvār (ஆழ்வார்) for Vaiṣṇavaite Tamil poet saints has historically been a corruption of the original Āḷvār (ஆள்வார்). Correction of the original Āḷvār (ஆள்வார்) to Āḻvār (ஆழ்வார்) Palaniappan shows that what was originally Āḷvār (ஆள்வார்) meaning 'One who rules', or '(Spiritual) Master' got changed through hypercorrection and folk etymology to Āḻvār (ஆழ்வார்) meaning 'One who is immersed'. Palaniappan cites inscriptional evidence and even literary evidence from Vaishnavaite tradition itself for a gradual sound change from Āḷvār (ஆள்வார்) to Āḻvār