Gautama Buddha (c. 563 BCE/480 BCE – c. 483 BCE/400 BCE), also known as Siddhārtha Gautama or simply Buddha, was an ascetic and sage, on whose teachings Buddhism was founded.
Gautama taught a Middle Way between sensual indulgence and the severe asceticism found in the śramaṇa movement common in his region. At the age of 29, Siddhartha left his palace to meet his subjects. Despite his father's efforts to hide from him the sick, aged and suffering, Siddhartha was said to have seen an old man. When his charioteer Channa explained to him that all people grew old, the prince went on further trips beyond the palace. On these he encountered a diseased man, a decaying corpse, and an ascetic. These depressed him, and he initially strove to overcome ageing, sickness, and death by living the life of an ascetic.
Following this incident, Gautama was famously seated under a pipal tree—now known as the Bodhi tree—in Bodh Gaya, India, when he vowed never to arise until he had found the truth. At the age of 35, he is said to have attained Enlightenment, and became known as the Buddha or "Awakened One" ("Buddha" is also sometimes translated as "The Enlightened One").
(source : Wikipedia) Write-up on Buddha