The Vedānta-darśana, one of the six systems of Indian philosophy, is based mainly on the Brahmasūtras, which again, is a work that systematizes the philosophical ideas occurring in the Upaniṣads.
Rāmānuja (A.D. 1107-1137) wrote an admirable commentary—the Śrībhāṣya—on the Brahmasūtras according to the Viśiṣṭādvaita philosophy and Vaiṣṇava religion. He is said to have acquired a copy of the Vṛtti (gloss) on the Brahma-sūtras written by an ancient teacher Bodhāyana, which was quite voluminous and which he (Rāmānuja) had faithfully followed while composing the Śrībhāṣya. Who this Bodhāyana was, is not known; nor is his work available. He is sometimes identified with Upavarṣa (also called Vṛttikāra), who again, had been known as Kṛtakoṭi and Halabhūti also. He is said to have written a vṛtti on the Pūrvamīmāṁsā-sūtras also. However none of these has been universally accepted by the scholars in these fields. It is generally conceded that Bodhāyana was, historically speaking, the founder of Vaiṣṇava schools of philosophy.