The Bhagavathas, in the Vedic times, developed Vaishnavism or devotional worship to Sri Vasudeva or Sri Narayana. Their own scripture was known as Pañcharathra Agama, regarded as equal to Upanishads. Later, Vaishnava Acharyas established the devotional path of worship for the realization of God, combining Karma and Jnana pathways to these teachings.

Sri Ramanujacharya wrote Sri-Bhashya, his commentaries on Brahma Suthras and gave us the philosophy, as the chief text of the system of Visishta-adhvaitha. The Visishta-adhvaitha system is an ancient one. It was originally explained by Sage Bodhayana in his Vritti. It is the same as followed by Sri Ramanuja in his interpretation of the Brahma Suthra. Sri Ramanuja accepts perception, inference and Scripture as valid sources of knowledge. He adopts the theories of Sathkara-Vaada and Parinama-Vaada, the doctrine of real effect proceeding from a cause. Sri Ramanuja also wrote a commentary on Bhagavat-Gita and other books known as Vedantha Sara, Vedhantha Sangraha and Vedhantha Dipa.

Sri Ramanuja explains Brahman as a personal God with attributes. Whatever exists, is Brahman; but It is not of a homogenous nature. It has elements of plurality and manifests in a diversified world. There is no room for Nirguna Brahman and Saguna Brahman or Isvara. It is Savisesha Brahman or Iswara with attributes. When Vedas describe Him as Nirguna, it means there is no base or lower qualities such as sorrow, pain, change or old age for Him. He is the essence of the soul and all-pervading. He is Sathya (Truth), Jñana (Knowledge) and Anandha (Bliss). He is Immanent, Transcendent and He is also unchanging. The entire Universe is latent in Him during Pralaya. The world is projected during creation, but this does not touch His essence. God, soul and Nature are three eternal entities. The soul is self-conscious, unchanging, partless and atomic. They are infinite in numbers and individual. It is eternally distinct from God. It has, indeed, sprung from Brahman, but is never outside Brahman and enjoys a separate personality. The individual soul is immersed in a worldliness or Samsara. It gets its body according to it's past Karma and gets reborn till the final emancipation. The liberated soul passes into a kind of paradise (Vaikuntha) which is the place of Sri Narayana.