Universal soul is one of the main Keystone of the philosophy and the thought of the Upanishad. Brahma satyam Jagat Mitya Jeevo Bramanah Parah talks about the impermenance of the body and its existence.
The third Sangam was held at the present Madurai in Tamil Nadu. The third sangam had 449 poets and the important ones among them include Nakkirar, Iraiyanar, Kapilar, Paranar, Sattanar, Auvikyar etc.