Before Siddartha was born and his mother had a dream that she was struck by a white elephant. According to the Brahmans that meant that he could have two paths, ruling the universe, or leave his royal life to become the Buddha. When he got older and left the castle he saw people suffering and wanted to find enlightenment.
Prince Siddhartha came across someone suffering in India. He didn't want that to happen so he wanted a path to enlightenment. Prince Siddhartha went to a tree in the woods and meditated. When he left the tree he had reached enlightenment and became the founder of Buddhism.
Siddhartha came back to the palace and shared his learning with others. He taught them about the Eightfold path and the Noble Truths. He was trying to teach peole to rid all of the evil in the world, and to stop suffering. Prince Siddartha taught everyone how to find enlightenment.