Zen, also known as Chan (in Chinese) or Seon (in Korean), developed from the teachings of the Indian monk Bodhidharma, who is thought to have lived sometime between the fifth and sixth centuries CE. Bodhidharma traveled to China and is credited with introducing the meditation practice known as "direct pointing to the mind," which focused on the present moment and sudden enlightenment.
The teachings of Bodhidharma were incorporated into Chinese Buddhism and eventually gave rise to the Chan tradition. As the Chan tradition grew in popularity in China, various schools of Zen Buddhism developed, each with its approach and practices. These schools later spread to Japan, Korea, and other countries, resulting in the various Zen schools that exist today.
Even while Zen Buddhism has undergone numerous alterations and variations over time, it still maintains foundational Buddhist teachings and insights, including the notion of no-self, the pursuit of enlightenment, and the value of meditation in achieving understanding. As such, Zen Buddhism is considered a legitimate and important tradition within the broader Buddhist religion, and its history may be traced back to the teachings of the Buddha.