A way of life based on farming and settled villages had been firmly achieved by 7000 BCE in the Tigris and Euphrates river valleys (now in Iraq and Iran) and in what are now Syria, Israel, Lebanon, and Jordan. The earliest farmers raised barley and wheat and kept sheep and goats, later supplemented by cattle and pigs. Their innovations spread from the Middle East northward into Europe by two routes: across Turkey and Greece into central Europe and across Egypt and North Africa and thence to Spain. Farming communities appeared in Greece as early as 7000 BCE, and farming spread northward throughout the continent over the next four millennia. This long and gradual transition was not completed in Britain and Scandinavia until after 3000 BCE and is known as the Mesolithic Period.