I think a little earlier. Religion, in particular Christianity, is responsible for create a massive conceptual divide between mankind, created in gods' image, a

I think a little earlier. Religion, in particular Christianity, is responsible for create a massive conceptual divide between mankind, created in gods' image, and everything else, lower life forms at our disposal. Another pivotal moment would be have to be the invention of agriculture, some 10K years ago. Only from this point on begins the idea of animals as property.