A short history of Buddhism:
In the year 534 BCE, a young Indian prince named Siddhartha Gautama (age 29) was deeply troubled about the fact that so many people suffer. So he left his wife and child and renounced his throne to find out the answer to why there was suffering. Now it should be noted when Buddhists speak of suffering this includes dissatisfaction (unhappiness) with the way things are. Siddhartha went to study with various gurus to try to find the answer to his question. Theses gurus had him do various types of yoga and meditation to try to help him with his quest. None of them seem to have an answer to his question though.
Siddhartha left these various gurus and joined in with a group of ascetics. Asceticism is a path in which you deprive the body in order to conquer and control the mind. He practiced asceticism fiercely, almost to the point of death. At that point he realized that giving in to pleasure, as he did when he was a prince, nor trying to punish the body, was the proper path to finding the answer. So he sat down and meditated under a pi-pal tree. During this meditation he discovered the root of all suffering and the path to how to overcome suffering and became enlightened.
After his enlightenment he meets up with his ascetic friends, who by now were critical of him for leaving the path of asceticism. But he explains to them what he had discovered and they were instantly converted. From there The Buddha taught for 45 years until his death at 85 converting many to his teachings and now Buddhism is the 4th largest religion in the world.