After Siddhartha Gautama was enlightened he became the Buddha. Before that time he had been first a great prince and then, after his renunciation, a wandering monk. His aim was to uncover the secret of suffering and find enlightenment. He tried several teachers, starved himself close to death, practised self-torture and meditation, but none of these worked. In despair he decided to sit under a Bo tree, not leaving until he had found either enlightenment or death. Four weeks later it came to him in the night. He ‘saw’ into the ultimate nature of reality: that it was without names, time or permanence. He realised that he was it and it he.
A few weeks after that he gave his first sermon in the Deer Park at Sarnath to five disciples. He told them that he had discovered that everything that arises is subject to cessation, including suffering. The path to enlightenment lay in the Four Noble Truths:
1. Know that there is dukkha
2. Understand the origin of dukkha in attachment
3. Let go of attachment and dukkha
4. Follow the Eight-fold path