The Hare Krishna mantra, also referred to reverentially as the Mahā-mantra ("Great Mantra"), is a 16-pit Vaishnava mantra mentioned in the Kali-Saṇṭāraṇa Upaniṣad. In the 15th century, it rose to importance in the Bhakti movement following the teachings of Chaitanya Mahaprabhu. This mantra is composed of three Sanskrit names – "Krishna", "Rama", and "Hare".
Since the 1960s, the mantra has been made well known outside India by A. C. Bhaktivedanta Swami Prabhupada and his movement, International Society for Krishna Consciousness (commonly known as the "Hare Krishnas" or the Hare Krishna movement).
The Hare Krishna mantra is composed of Sanskrit names: Hare, Krishna, and Rama (in Anglicized spelling). It is a poetic stanza in anuṣṭubh meter (a quatrain of four lines (pāda) of eight syllables with certain syllable lengths for some of the syllables).
The mantra as rendered in the oldest extant written source, the Kali-Saṇṭāraṇa Upaniṣad, is as follows: