the first people to speak about evolution were empedocles and other greek philosophers in europe (5th century bce), taoism in asia. the history of evolutionary thought in christian theology dates back to augustine of hippo (4th century) and thomas aquinas (13th century). the modern creation–evolution controversy started in europe and north america in the late 18th century. discoveries in geology led to various theories of an ancient earth, and fossils showing past extinctions prompted early ideas of evolution. these ideas were particularly controversial in england, where both the natural world and the hierarchical social order were thought to be fixed by god's will. as the terrors of the french revolution developed into the napoleonic wars, followed by economic depression threatening revolution in great britain itself, such subversive ideas were rejected, associated only with radical agitators.