Sri Madurakavigal had performed prathistai of swami nammalwar by boiling thaarabarani river. This vaibhavam happend in Maasi Visakam hence it;s called pratistai utsavam.

This is akin to Guru Pushyam (Swmi emberumaanar tiruprathistai utsavam in Thai Poosam)

Thanks SrI Srivathsan Krishnan swamy for the photos and brief of the utsavam