Zorostrianism (6th century B C ) precedes all other religions known to mankind.
The second Isaiah juxtaposes the great Persian King Cyrus with the first monotheistic declarations in the Bible. The second Isaiah is the first expression of universalism which has no antecedent in the Bible, according to the Anchor Bible note at Isaiah 45. He also first introduces the idea of false gods -- a fundamental and indispensable criteria for monotheism.
A universal God determines that only one is worshiped; a tribal god, of necessity, implies polytheism since there are other tribes. Before the exile, God was a vengeful, bloodthirsty, and jealous anthropomorphic tribal God of fear. After the exile, He became a good, perfect, remote, and universal God of love: identical to Ahura-Mazda of the Zoroastrians. It needed the subsequent missions of Nehemiah and Ezra backed by the Achaemenian Imperial Government's authority to make the Jews ruefully conform to the new ideal of monotheism.
Zoroastrian had evolved, if you must know, from Mithras, which is a Zoroastrian sub-cult.
