Complex sentence: No Egyptian archaeological evidence exists of iron smelting until 6th century BC. The earliest known example of the use of metallic iron in Egypt dates to approximately 3400BC, this corresponds to the pre-historic time before Egypt became a single state ruled by a pharaoh.
Split into simpler sentences: No Egyptian archaeological evidence exists of iron smelting until 6th century BC. The earliest known example of the use of metallic iron in Egypt dates to approximately 3400BC. This corresponds to the prehistoric time before Egypt became a single state ruled by a pharaoh.