Is it true that Yahweh was part of a polytheistic religion?

I remembered recently that long ago, in middle school, my history teacher told us in the class that Yahweh, the Hebrew God was a god part of a polytheistic religion, and that He wasn't even the king of gods(like Zeus from Greek religion), and that Abraham choose Him(Yahweh) from the other gods to be the all-mighty, all-knowing, all-powerful, single God to his new monotheistic religion, that he passed to his son Issac and his grand-son Israel and it became the God of Israel nation and trough Jesus(who was part of the Israeli nation, kingdom of Judah), it became God-The Father for us, Christians. This sounds like a blasphemy to me, but is this based on any historical discovery, or has it any theological or historical veracity?