Āḷāra Kālāma 

One of the Buddha's first two teachers, the other being Udraka Rāmaputra. After renouncing the world the Buddha became Āḷāra's student. The precise nature of Āḷāra's teachings is unclear, but they involved a meditational practice which enabled one to reach a profound state of trance known as the ‘sphere of nothingness’ (Pāli, akiñcaññāyatana), later equated with the seventh dhyāna of classical Buddhist meditation theory. Before long the Buddha surpassed his teacher and took leave of him to continue his religious quest. Āḷāra died shortly before the Buddha achieved enlightenment (bodhi).

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)