Darwin's religious beliefs have always been a matter of controversy, not least because like many of us he fluctuated. His loss of faith in a BENEFICENT God is well documented, but in a letter written in 1879 (three years before he died) he himself claimed that he had "never been an Atheist in the sense of denying the existence of a God." He went on to say: "an Agnostic would be a more correct description of my state of mind." - What is crucial to this discussion is that, despite the misleading claims of Darwin's atheist interpreters, evolution - in the context of intelligent design - is not incompatible with theism. In the same letter quoted above, Darwin says explicitly that one "can be an ardent Theist and an evolutionist."
 
It IS incompatible, though, with fundamentalist Creationism ... i.e. the idea that God created every species individually and simultaneously on the sixth day.