The Bodhisatta was once a naked ascetic. He lived dirty, emaciated, and alone, deep in the forest, in his quest to learn the truth about life. He ate small fish, cow dung, and other refuse and fled when other humans came near. In the snows of winter he slept out in the open, and in the heat of summer he slept in a thicket, away from cooling winds. He embraced this insufferable existence for his entire adult life, but as he lay dying, he had a vision of hell and knew his life had been worthless. After this realization, he died free of his delusions and was reborn in heaven.
In the Lifetime of the Buddha
One of the Buddha’s disciples left the sangha to follow another religious teacher who promoted extreme asceticism. While out on a morning alms round, Sariputta, one of the Buddha’s top disciples, heard this former disciple criticizing the Buddha for not being superhuman and saying his doctrine did not lead to the destruction of sorrow.
When Sariputta told the Buddha what he had heard, the Buddha listed some of his abilities and explained that people who spoke heresy such as this would be cast into hell if they did not renounce it. Then the Buddha told this story of his past life as a repulsive naked ascetic to show that this path was ineffective.
The Buddha did not identify any earlier births other than his own.