Complex sentence: Historian of science John Henry has noted that before the 19th century science was generally used to support many theological positions, however, since materialist theories in natural philosophy became more fundamental in the 17th century onwards, this gave more room for atheism to develop.
Split into simpler sentences: Historian of science John Henry has noted that before the 19th century, science was generally cited to support many theological positions. However, materialist theories in natural philosophy became more prominent from the 17th century onwards, giving more room for atheism to develop.