He didn't support any religion; he had a tolerance policy regarding those he conquered and allowed them to follow any religion they chose. He did this so the people would be satisfied under his rule and not revolt.
Answer2: The indications are that the kings of Medo-Persian Empire were Zoroastrians. While it cannot be proved or disproved that Cyrus the Great adhered to the teachings of Zoroaster, from the time of Darius I the inscriptions of the monarchs repeatedly refer to Ahura Madza, the principal deity of Zoroastrianism. Darius I referred to Ahura Mazda as the creator of heaven, earth and man and he looked to this god as the one who had bestowed upon him wisdom, physical skillfulness and the kingdom.
He saw it as a unifying force, just as he encouraged Aramaic as a lingua franca.
Zoroastrianism
Great King Darius Great King Darius
There were several Persian leaders called Darius - they were kings of Persia.
zoroastrianism
Darius was a Persian.
Zoroastrianism was Persia's official religion. The Avesta is the holy book of the adherents of Zarathustra, the Zoroastrians, the supreme god Ahuramazda. King Darius says: Ahuramazda has granted unto me this empire. Ahuramazda brought me help, until I gained this empire; by the grace of Ahuramazda do I hold this empire. The ancient Persian religion was called Zoroastrianism. The religion has adherents to this day. Currently, the main Persian religion is Islam.
Many believe Darius the Great was the King of Persia who introduced and followed the teachings of Zoroaster (Zoroastrianism).
darius I darius I
Persian King
Persian King
darius used some of persian's great wealth to build roads across the empire