Zoroastrianism supplanted Buddhism in ancient India, which extended into Persia. Eventually Zoroastrianism gave way to Islam and Iran (Aryan) invasions spread throughout the middle country (northern India). The waves of military conquests and successions of kings melts into repetitive history in the Mahabharata and other Indian classics. The Bodhisatta ("Buddha-to-be") arose out of this milieu and went in search of enlightenment as a stranger in a strange land in what today is Bihar State.
He consummated his six year odyssey in Bodhgaya and spent most of the remainder of his life teaching in ancient India's two largest cities, Savatthi and Rajagaha. His message, however, has reverberated throughout the world. It influenced the Greeks and therefore Western civilization, adopting the guise of each culture it blended with.
He is often called the Light of the East. But his range of influence is one of the Four Imponderables. Rare is a human life; rarer still is meeting with the Buddha-Dharma. The opportunity to practice is precious, encouraging every good thing until we realize the "end of suffering" (nirvana).