During the great deluge known as the pralaya, when the rising seas threatened to destroy the entire world, Lord Shiva adorned himself with all the 64 art forms and fashioned the sacred Pranava mantra into a sturdy boat. Accompanied by his divine consort Umadevi, Shiva set out to navigate the tumultuous floodwaters. As they journeyed across the endless expanse of the raging seas, they came upon the town of Sirkazhi, which alone had been spared the devastation that had ravaged all other lands. Recognizing this place as the primordial site of creation, Shiva declared to Umadevi that they would remain here. Shiva came to be revered as Thoniyappar, the "Lord of the Boat." Furthermore, Brahma had worshipped Shiva before resuming the work of creation following the great deluge, the deity is also honored in this place as Brahmapureeswarar.

This towering Shiva temple, centrally situated in the town of Sirgazhi, is an awe-inspiring architectural marvel that commands attention from all who behold it. The temple features an impressive four gateways, each adorned with a massive, intricately-carved gopuram that rises high into the sky, serving as a beacon for devotees. The eastern gateway in particular is designated as the main entrance. As one crosses the threshold of the eastern entrance and proceeds inward, the first sannidhi, that comes into view is that of Brahmapureeswarar. This sannidhi is oriented towards the east and situated near the temple's sacred pond. To the right of Brahmapureeswarar stands the "Urchava" idol of the child-saint Gyanasambandhar, who is depicted holding a small bowl in his hands - a symbolic representation of the divine milk of wisdom that the Goddess herself bestowed upon him. Continuing further into the temple complex, one arrives at the northern section, where the sannidhi of the goddess Thiru-Nilai-Nayaki can be found, opposite 'Brahma Theertham'. It was on the very banks of Brahma Theertham that Gyanasambandhar received 'Gyana-Paal' from Goddess Parvathy. The final sannidhi, dedicated to Thoniappar, along with his consort Periya-Nayaki, is located on an elevated level within the temple. A set of narrow, wooden stairs from this sannidhi, leads devotees up to another level, which houses the south-facing sannidhi of Sattai-Nathar. The temple is renowned by this latter name as well, with specific protocols observed by visitors - men must remove their shirts before climbing the stairs, and women are expected to remove any flowers from their hair before going up to see Sattai-Nathar.