Since the dawn of mankind, Western Europe was occupied by hunter-gatherers and fishermen. That changed with the invention of agriculture, around 5 000 BC. Due to agricultural progress, towns began to develop in the area called Fertile Crescent, and that resulted in demographic expansion. The agricultural techniques and tools spread north and west into Anatolia, thus promoting livestock farming and the planting of wheat and barley crops. In time, agricultural progress reached the Balkans and followed the course of the great rivers such as the Danube, Elbe, and Rhine, and other corridors of development opened the way to the Italian peninsula and the Rhon valley.