Poigai Alvar was one of the twelve Alvars and was a Hindu saint. He belonged to the Vaishnava (worshiper of Vishnu) denomination of Hinduism.

   Poigai Alvar was born in a village near Kanchipuram in the seventh century CE. Poigai (pond in Tamil) was found as a baby near a pond of a Vishnu Temple. Some Vaishnavas consider him to be an incarnation of Panchajanyam, the divine conch of Vishnu. Poigai Alvar's 100 hymns form the beginning of the Naalayira Divyap Prabhandham. Poigai Alwar's hymns start with the words Vaiyam Tagaliya, Varkadale Neyyaaga (I am singing these garland of verses (pashurams) and dedicating to Him, whose vision I had is the light of the lamp of the earth, and oil being the seas, the sun being the source of the light).

   Source : http://en.wikipedia.org/wiki/Poigai_Alvar

Some Vaishnavas consider him to be an incarnation of Panchajanyam, the divine conch of Vishnu...(In the wallpaper: Shri Krishna in the right, Conch, Poigai Alvar).