Monotheism
Who
Ancient Israelites and the Hebrew Bible; Judaism is the oldest continuously practised monotheistic religion, and no single individual founded it.
When
1st millennium BCE (formative period)
Where
Ancient Israel / the Levant
The belief in one God is expressed most enduringly in the Hebrew Bible and the religion of ancient Israel, from which Judaism developed. This monotheistic tradition became the shared root of Christianity and Islam, shaping the ethical and religious outlook of much of the world.
Sources
Part of “The Gifts of the Jews” — verified Jewish contributions to the world, with sources.