Buddhism is based on the beliefs of the Buddha, who set forth a new "religion" was different from the other world religions. It is a religion that was based on the in all lives there are four passing, and the Buddha's six rejections of Hinduism. It allows Buddhists to take refuge in the Buddha and his life, which include the four passing of life, and in his teaching of The Four Noble Truths. Finally it expresses the difference between nirvana and moksha.
The story of the Buddha is told through the legend of The Four Passing Sights. It tells the story of a father who wants to keep his son attached to this world and to keep him from becoming a world redeemer. The father a king spared no expense shielding the prince from contact with sickness, decrepitude and death. However, one day the prince saw an old man and learned of old age. The next day he saw a man racked with disease and the on the third he saw a corpse. Finally on the fourth day he saw a monk. This led to his belief that "Life is subject to age and death. Where is the realm of life in which there is neither age nor death?" This led to his great going forth. He left his wife and child and plunged into the forest in search of enlightenment.
In the Buddha's search for the extreme spiritualism he spent the next six years concentrating his full energies on looking for answers to his questions. I believe that it was the questions that led to his criticism of Hinduism. His first sop was to seek out two of the leading Hindu masters and to pick their brains for their wisdom. He learned a lot about yoga and Hindu philosophy. His second stop was to join a band of ascetics and give this lifestyle a try. He was a man of enormous will power. He went so far as to exist on six grains of rice a day during on fast. However, he did not find enlightenment in this. His third and final stop was devoted to the "combination of rigorous thought and mystic concentration along the lines of raja yoga.