Sri Krishna Caitanya Mahaprabhu honorific: "Mahāprabhu" ("Great Lord"), was a Bengali Hindu mystic, saint, and the chief proponent of the Achintya Bheda Abheda and Gaudiya Vaishnavism tradition within Hinduism. He also expounded the Vaishnava school of Bhakti yoga (meaning loving devotion to God), based on Bhagavata Purana and Bhagavad Gita. Of various forms and direct or indirect expansions of Krishna such as Lord Narasimha (Krishna in mood of anger), Maha-Vishnu and Garbhodakshaya Vishnu respectively, he is Krishna in the mood of a devotee. He popularised the chanting of the Hare Krishna mantra and composed the Siksastakam (eight devotional prayers) in Sanskrit. His followers, Gaudiya Vaishnavas, revere him as a Krishna with the mood and complexion of his source of inspiration Radha. His birthday is celebrated as Gaura-purnima.