After he had left his father's castle, however, the unrest did not cease in the Prince's heart, and many demons tempted him, saying, "It would be better for you to return to the palace and find some other solution: then the whole world could belong to you." But he was able to silence these demonic voices by realizing that nothing worldly could ever satisfy him. So he shaved his head and turned his steps south, carrying an alms bowl in his hands.

This irrevocable, unquestionable and unreturnable decision is called "the awakening of the aspiration to Buddhahood". It has always been the indispensable starting point when one undertakes to walk the path of the Buddha.

Gautama first sought a master. The Prince visited first Ālāra Kālāma, then Uddaka Rāmaputta to follow their teachings and practices. From the first, he learned about nothingness, the state of life in which one is not attached to unlimited space or one's own consciousness. From the second, he learned the "dimension of neither perception nor non-perception," a state of life in which one is free of ordinary discriminatory thought and retains only the barest traces of discriminatory thought. Both methods of practice, based on meditations, were in fact only mental calm. But stillness does not uproot the causes of suffering. It can only bring temporary peace, which is why Gautama rejected them. This was not liberation. The Buddha awakened to the fact that true freedom is without desire, without attachment and without self. Quickly disappointed with these masters, whom he surpassed after two months, he went to Magadha and followed his own asceticism of mortifications, of terrible fasts in the forest of Uruvilva, on the banks of the Nairanjana, the river which flows near the castle of Gaya. His training was incredibly severe. He stimulated himself with the thought, "No ascetic in the past, present, or future has practiced, practices, or will practice more severely than I do." But the Prince still could not reach his goal. After six years (12 according to another theory) in the forest, he rejected all ascetic practice. He bathed in the river and accepted a bowl of milk from Sujata, a servant girl who lived in the nearby village.

The five companions who had lived with the Prince for all those years, sharing his life of austerity, were scandalized to see him accept milk from a servant. They thought he had fallen from grace and left him.

So the Prince was left alone. He was still weak, but at the risk of his life he tried a new period of meditation, saying to himself, "Though my blood should run dry, my flesh wither, my bones fall to dust, I shall not leave this place until I have found the way to enlightenment."

Finally, he sat down one evening under a Ficus religiosa and, engaged in an intense and incomparable struggle. His heart was desperate and filled with confused thoughts, dark darkness covered his mind, he was invested by all the lures of demons. But with care and patience he looked at them one by one and eliminated them one by one. It was truly a hard fight: his blood oozed, his flesh withered, his bones cracked. However, when the morning star appeared in the eastern sky, the battle was over and the Prince's mind was as clear and bright as the dawn. He had finally found the path to unparalleled enlightenment. He experienced the absolute. He identified himself with the absolute. He understood the unique and universal principle of life and death, he perceived the true aspect of things. It was on December 8, when he was 35 years old (30 according to another thesis), that the Prince became Buddha.

From that time on, the Prince was known by various names. Some called him Buddha (the Enlightened One - 仏); others, the All-Illuminated One (Dai Gaku - 大覚); still others called him Śâkyamuni (釈迦牟尼), the "Sage of the clan of Śâkyas," and still others called him World Worshipful (Seson - 世尊).

Freed from all suffering, he thought that he would not preach because what he had realized would be too difficult for ordinary people who had not practiced anything to understand and would be misunderstood. Brahmā, who was concerned about this, descended from the heavens to the Buddha and advised him to preach by explaining the diversity of sentient beings. The Buddha was moved with compassion at the thought of men still trapped in their illusions, stuck in the quicksand of delusion, suffering in a chimerical world. Their reality was only a dream, a bad dream for the now Buddha (awakened). He was determined to awaken them in turn, to rescue them from their nightmare. He declared to Brahmā that he would preach with compassion and Brahmā happily disappeared.

But how to do it? How to share his unique experience? Especially since, even if he explained the truth to them and even if they were capable of understanding it intellectually, they had to live it, experience it through practice.

It is in this context that Gautama set the wheel of Dharma in motion. To do this, He first went to the Gazelle Park (Mrigadava) in Benares, where he addressed the five men who had followed him in his philosophical and ascetic journey from the beginning. Their names were Ājñāta Kauņdinya, Aśva Jit, Bhadrika, Vāşpa and Mahā Nāman. The first two were maternal relatives of Gautama and the other three were relatives on his father's side. The latter, King Śuddhodana had actually dispatched them to his son, in order to protect him.

The now Buddha, could not find a better audience to test the beings' understanding of the truth.

At first, they tried to avoid him, but when he spoke to them, they believed in him and became his first disciples. Then he went to Rajagriha Castle and converted King Bimbisara, who had always been his friend. From there he traveled throughout the region, living on alms and converting people so that he could lead them to enlightenment as well.

People responded to him like thirsty people seeking water or hungry people seeking food. Two great disciples, Śariputra and Maudgalyayana came to him with their two thousand students.

At first the father of the Buddha, King Śuddhodana, still all saddened within himself at the decision the Prince had made to leave the palace, kept away, but later he became his faithful disciple; Mahaprajapati, the Buddha's mother-in-law, Princess Yaśodhara, his wife, Rahula, their son, and all the members of the clan of the Śâkyas believed in him and followed him. And many other people became his devoted and faithful followers.