Monotheism was a significant historical development of the first millennium BC/BCE. Why was it so important?

The development of monotheism has left a strong mark on today's modern society.

Explanation:

Monotheism implies belief in one god. This form of view has a lengthy historical background. Christianity, Islam, Judaism are a touching product of monotheism that is still evident today. The first monotheistic cult was brought by the Egyptian Pharaoh Amenophis IV, who introduced the belief in Athos, that is, the solar disk. Subsequently, in many religions, the supreme god became more and more distant from humans and was placed in heaven. The development of monotheism is significant because it is a dire product of the ancient world, which is most evident in today's modern world.

most people were factory or company owners.

the answer is mass marketing.