Final answer:
Zoroastrianism is considered the world's first monotheistic religion, originating from ancient Persia, with a complex theology involving a struggle between good and evil. It has significantly influenced other monotheistic religions and continues to have cultural significance today.
Step-by-step explanation:
Many regard Zoroastrianism as the first monotheistic religion in the world. Zoroastrianism is a universal faith with elements of both monotheism and dualism based on the teachings of the prophet Zoroaster, who is believed to have lived at some point between 1400 and 900 BCE. The religion, established prominently by King Ardashir as the state religion of ancient Persia, encouraged loyalty through a highly developed ethical code and rituals of purification.
Adherents of Zoroastrianism are expected to carry out good deeds, maintain good thoughts, and practice purification rituals. The religion centers around the continuous struggle between Ahura Mazda, the god of creation and goodness, and his archenemy, the spirit of evil and darkness. Zoroastrianism's influence is evident in the development of other monotheistic religions such as Judaism, Christianity, and Islam, especially in themes of morality, the afterlife, and salvation.
The once-dominant religion in Greater Iran has now dwindled in numbers but remains relevant. Its rituals, especially those that involve fire regarded as a holy force, and the Persian New Year, Nouruz, show Zoroastrianism's lasting cultural impact.