When did people start believing in one god?

The belief in one god, known as monotheism, began to emerge around the late 2nd millennium BCE, notably with the worship of Yahweh in ancient Israel. This concept was distinctly articulated in the Hebrew Bible and became more prominent during the time of the Babylonian Exile in the 6th century BCE. Other monotheistic traditions, such as Zoroastrianism, also contributed to the development of this belief around the same period. Ultimately, the spread of monotheism was significantly influenced by the emergence of Christianity and Islam in the first millennium CE.