The most commonly used steel was bronze, of which numerous examples have survived, for example, headrests for couches and steel stools. Similar to the Greeks, Romans used tenons, dowels, nails, and glue to join picket items collectively, and likewise practised veneering. Civilization in historic Egypt started with the clearance and irrigation of land along the banks of the River Nile, which started in about 6000 BCE. By that point, society in the Nile Valley was already engaged in organized agriculture and the construction of huge buildings. At this period, Egyptians within the southwestern nook of Egypt had been herding cattle and in addition developing large buildings.