Who started the teaching of buddha?

The teachings of Buddhism were initiated by Siddhartha Gautama, who became known as the Buddha, meaning "the Enlightened One." After attaining enlightenment in the 5th century BCE, he began to share his insights on suffering, the nature of existence, and the path to liberation. His first sermon, known as the Dhammacakkappavattana Sutta, was delivered in Sarnath, where he outlined the Four Noble Truths and the Eightfold Path. His teachings laid the foundation for Buddhism as a major world religion.