Śrī Vaiṣṇava Sampradāya — The Tradition of Ubhaya Vedānta
Śrī Vaiṣṇava Sampradāya is one of the four principal Vaiṣṇava traditions (sampradāyas) recognized in medieval Hindu theology — the others being the Brahma (Mādhva), Rudra (Viṣṇusvāmi/Vallabha), and Kumāra (Nimbārka) schools. It is distinguished by its unique philosophical position of Viśiṣṭādvaita (qualified non-dualism), its Guru-paramparā tracing from Śrī Mahālakṣmī through Viṣvaksena, the Āzhvārs, Nāthamuni, Āḷavandhār, and Rāmānuja, and its acceptance of the Divya Prabandham (4,000 Tamil verses of the Āzhvārs) as equal in authority to the Sanskrit Vedas — a position called Ubhaya Vedānta (dual Vedānta).
The Āchārya Lineage: The tradition holds that the sampradāya flows from Nārāyaṇa Himself, who instructed Nammāzhvār through the medium of Śrī Nāthamuni (9th century CE). Nāthamuni recovered the 4,000 Divya Prabandham pāsurams and established the structural foundations of the tradition. Āḷavandhār (10th c.) consolidated its Vedāntic philosophical framework. Rāmānujāchārya (1017–1137 CE) systematized the theology in the Śrī Bhāṣya, Gītābhāṣya, and Vedārthasaṅgraha, and instituted the 74 Siṃhāsanādhipatis to propagate the tradition.
Ubhaya Vedānta — Dual Scripture: The defining characteristic of Śrī Vaiṣṇava Sampradāya among all Vedāntic schools is its reception of Tamil scripture as Vedic in authority. The twelve Āzhvārs are understood not as human poets alone but as divinely inspired transmitters of the same truths carried in Sanskrit scripture. Nammāzhvār's Tiruvāymozhi is explicitly equated with the Sāma Veda.
The Two Sub-schools: By the 13th–14th centuries CE, the tradition bifurcated into the Teṅkalai (Southern school, Pillai Lokāchārya and Maṇavāḷa Māmunigaḷ) and Vaḍakalai (Northern school, Vedānta Deśika). Their differences concern the nature of grace and the path of prapatti, but both share the foundational commitments to Viśiṣṭādvaita, the Guru-paramparā, and Ubhaya Vedānta, and both venerate Rāmānuja as the premier Āchārya.