Early signs of these hunter-gatherers beginning to harvest, select and grow various food plants have been found in the Mesolithic Natufian culture of the Levant. These are signs that would later lead to the actual domestication and farming of crops. Archaeologists believe that the Levantine peoples developed agriculture between 8000 and 7000 BC in response to a rise in their population levels which could not be fed by the food which hunting and gathering could provide. The idea of agriculture spread from the Levant into Europe, being adopted by hunter-gathering societies in what is now Turkey, Greece, the Balkans, and across the Mediterranean, eventually reaching north-western Europe and the British Isles.