Naropa
Naropa was born a high status Brahmin and from an early age showed strong,  highly intelligent mind. At the age of 28 Naropa entered the famous Buddhist University at Nalanda where he studied both Sutra and Tantra. He had the reputation of a great scholar and debater. Later Naropa became studend of Tilopa and spent twelve years with him. While studying and meditating with his teacher Naropa met and overcame twelve minor and twelve major hardships. Eventually he reached full realization and become teacher of Marpa.