 The tradition was founded by Nathamuni (10th century), who along with Yamunacharya, combined the two traditions and gave the tradition legitimacy by drawing on the Alvars.Its most influential leader was Ramanuja (1017-1137), who developed the Visistadvaita ("qualified non-dualism") philosophy.Ramanuja challenged the then dominant Advaita Vedanta interpretation of the Upanishads and Vedas, by formulating the Vishishtadvaita philosophy foundations for Sri Vaishnavism from Vedanta.