According to Bengali Polymath and Nobel Prize winner Rabindranath Tagore:

The first major change in human perception about religion and worship was the teachings of the ancient Iranian reformist and philosopher Zoroaster… [experts in the field date Zoroaster to 1700-1400 BCE]…

Tagore claimed in his book “The Religion of Man” (1931) that there is hardly any doubt that Zoroaster was the first person we know who gave moral character and direction to religion while teaching monotheism… Zoroaster broke the tradition of keeping people bound with external observances by preaching the path of Free Will…

Tagore viewed Zoroaster as the first to address all humanity with his teachings… “the Ideal of Zoroastrian Persia is distinctly ethical”…the heroic element of Zoroastrianism is based on the character of Iranians as a people… their heroism led to the creation of great empires…Iranians influenced others such as Judaea and Europe… “Their ideal was the ideal of the fighter”… that is, “by force of will and deeds of sacrifice they were to conquer … welfare in this world, and … immortality in the other. This is the best ideal in the West, the great truth of fight. For paradise has to be gained through conquest”… Tagore believed this ideal of a moral fight took a stronger hold on those in the West than in India…

[pic LACMA:  Iranian hero Rustam slays the white monster; folio from The Shahnameh or The Book of Kings… Mughal India (1608)… symbolically, the white monster is also the beast within oneself…for educational purposes only]