Egyptian civilization begins during the second phase of the Naqda culture, known as the Gerzeh period, around 3500 BC and coalesces with the unification of Upper and Lower Egypt around 3150 BC. Farming produced the vast majority of food; with increased food supplies, the populace adopted a much more sedentary lifestyle, and the larger settlements grew to cities of about 5,000 residents. It was in this time that the city dwellers started using mud brick to build their cities, and the use of the arch and recessed walls for decorative effect became popular. Copper instead of stone was increasingly used to make tools and weaponry. Symbols on Gerzean pottery also resemble nascent Egyptian hieroglyphs. Early evidence also exists of contact with the Near East, particularly Canaan and the Byblos coast, during this time. Concurrent with these cultural advances, a process of unification of the societies and towns of the upper Nile River, or Upper Egypt, occurred. At the same time the societies of the Nile Delta, or Lower Egypt, also underwent a unification process. During his reign in Upper Egypt, King Narmer defeated his enemies on the Delta and merged both the Kingdom of Upper and Lower Egypt under his single rule.