Tilopa (989-1069)

One of the famous Indian mahā-siddhas or great tantric adepts, his name derives from the tradition that he was a manufacturer of sesame-seed oil. Believed to have been the first teacher who expounded the mahāmudrā (Great Seal) doctrines and practices, he passed these and other tantric teachings to his disciple Nāropa who in turn passed them on to Marpa.

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