Silver is known by the mankind since Pre-History, and its discovery is estimated happened to shortly after that of copper and gold. The oldest reference to the element appears in the book of Genesis. The Egyptians considered gold to be a perfect metal, and gave it the symbol of a circle. Since silver was the closest to gold in perfection, it was given the symbol of a semi-circle. Later this semi-circle led to a growing moon symbol, probably due to the likeness between the shining metal and the moon glow. The Romans called silver argentum, keeping this as the international name of the element, from where its chemical symbol derives.