The first Sermon of the Buddha, the Dhammacakkappavattana Sutta, is commonly known as The Great Discourse on the Wheel of Dharma.
Being the First Sermon ever delivered by the Budha it is the most ancient and the most straightforward of his teachings. Buddhist followers regard this Sutta with great esteem and veneration as it was the First Dispensation of the Buddha. The introduction gives the background story of the Buddha. This provides an account of how the Bodhisatta, the future Buddha, fulfilled the perfections required of an aspirant Buddha.
Click on The Great Discourse on the Wheel of Dharma to read a translation of the entire discourse.