The Great Mother at Śrīraṅgam
Periya Pirātti (Tamil: பெரிய பிராட்டி, 'The Great Lady') is the name given to Śrī Lakṣmī as enshrined at Śrīraṅgam, where She is known as Ranganāyakī ('Lady of Raṅga'). She is 'great' (Periya) in distinction from Āṇḍāḷ, who is called the Nācciyār — both are forms of Śrī, but Mahālakṣmī is the supreme manifestation.
The Purushakāra Role
Periya Pirātti plays the crucial role of purushakāra (mediator) in Sri Vaishnava theology. Devotees first approach Her, and She, being ever-merciful, intercedes with the Lord on their behalf. She says to the Lord, in effect: 'Your child has come seeking refuge — please receive them.' The Lord, already gracious, is moved to even greater mercy by Her intercession.
Threefold Mediation
The theological sequence: (1) the devotee approaches Periya Pirātti; (2) She mediates with Ranganātha; (3) the Lord grants grace. This is why the Dvayam mantra begins with śrīman nārāyaṇa caraṇau — both names invoked together, because the Lord's grace flows through Śrī.
Her Independence in Grace
Periya Pirātti is not merely the Lord's consort in a domestic sense. She is herself the supreme source of compassion. The Lakṣmī Tantra and other Pañcarātra texts present Her as Śakti, the divine power through whom all creation and grace flow. In Śrī Vaishnava theology, Śrī and Nārāyaṇa together constitute the full divinity.