Atheism is the belief that God does not exist. The prefix “a” means no, or not. Theism is the belief that God exists. Atheists believe a variety of different things, as it isn’t a unified or centralized group. However, all atheists share the belief that there is no God.
Historians have traditionally acknowledged the impact of Judaism and Christianity on western culture. That's no surprise. What IS surprising is the modern trend of atheists defending biblical values. Skeptics like Tom Holland, Richard Dawkins, and Jordan Peterson are now willing to admit that the values of Christianity are not only good, but necessary for human flourishing.