Zoroastrianism is the religion and philosophy based on the teachings ascribed to the prophet Zoroaster (Zarathustra, Zartosht). Mazdaism is the religion that acknowledges the divine authority of Ahura Mazda, proclaimed by Zoroaster to be the one uncreated Creator of all (God). As demonstrated by Zoroastrian creed and articles of faith, the two terms are effectively synonymous.
Other basic beliefs include creation is attacked by violence and destruction. The resulting conflict involves the entire universe, including humanity, which has an active role to play in the conflict. Ahura Mazda will ultimately prevail, at which point time will end. Active participation in life through good thoughts, good words and good deeds are necessary to ensure happiness and to keep the chaos at bay. There is a concept of free will, to decide whether to perform good thoughts, words and deeds.
Zoroastrianism was once the dominating religion of much of Western- and Central Asia but is today practiced only by a small worldwide community, with its largest center in India.