Buddhism originated on the Indian subcontinent and survived through its ability to adapt to different cultures by applying what are known as “skillful means.” It developed within the context of earlier Brahmanic and Jain systems of thought, rejecting caste distinctions and asserting that everyone possesses the Buddha-nature factors that enable them to attain enlightenment. Shakyamuni Buddha based his teachings on the four true facts concerning life’s problems, their causes, their stoppings and the true paths of mind that eliminate confusion. As Buddhism spread over the centuries, its early orally transmitted teachings were compiled, and eighteen schools of Hinayana developed, primarily emphasizing the attainment of individual liberation. Mahayana subsequently emerged with the more extensive aim of attaining enlightenment for the benefit of all beings, while tantra later introduced advanced methods of visualization and working with the subtle energy-system of the body. These developments in Buddhist philosophical thought were furthered by the establishment of great monastic universities, such as Nalanda, where the various tenet systems were systematically studied, debated and refined. Although Turkic invasions eventually destroyed these Indian monasteries and brought Buddhism in its homeland to an end, the Buddhist teachings continued to survive by spreading to other lands.