This seemed to bring things to a climax and he decided to leave his palace home and seek the solution of his mental unrest in the homeless life of a mendicant. This plan he carried out one night, by leaving the castle with only his personal servant, Channa, and his favorite horse, the snow-white Kanthaka, and even these he left behind him when he had crossed the river at the b ounds of his Father's kingdom.
But his mental troubles were not at an end and many doubts beset him. "Perhaps it would be better for me to return to the castle and seek some other solution; then the whole world will be mine." But he resisted these doubts by realizing that nothing worldly could satisfy him. So he shaved his head, carried a begging bowl in his hand, and turned his mendicant steps to the south.
[...]
Still, the Prince could not get what he sought. After six years in the forest he gave up the practice of asceticism. He bathed in the river and accepted a bowl of food from the hand of Sujata, a maid who lived in the neighboring village. The five companions who had lived with the Prince for the six years of his ascetic practices looked on with amazement that he could receive food from the hand of a maiden; they thought him degraded thereby and left him. The Prince, thus, was left alone. He was still feeble but at the risk of his life he attempted a final meditation, saying to himself, "Blood may become exhausted, flesh may decay, bones may fall apart, but I will never leave this place until I find the way to enlightenment."
It was an intense and incomparable struggle! His mind was desperate, was filled with confusing thoughts, dark shadows overhung his spirit, he was beset with all the lures of evil. But carefully and patiently he examined them one by one and rejected them all. It, indeed, was a hard struggle, that made his blood run thin, his flesh creep, and his bones crack. But when the morning star appeared in the eastern sky, the struggle was over and the Prince's mind was as clear and bright as the day-break. He had found the path to enlightenment at last. It was December the 8th, when he was thirty-five years of age that the Prince became Buddha.
The Buddha's Life [Link]