"Gold is for the mistress -- silver for the maid -- Copper for the craftsman cunning at his trade."
"Good!" said the Baron, sitting in his hall,
"But Iron -- Cold Iron -- is master of them all."
Iron is the metel element that largly replaced Bronze as the principle metel for military use after the after the end of the Bronze Age. Iron was used during thee Bronze age with limited success and and didn't start to develop until after Bronze started to fall out of use.
Early Iron is actually weaker than worked Bronze for the period, and is generally accepted to if risen in popularity do to the scarcity of tin for making Bronze, where as Iron is far more abundant and for most uses was sufficient to replace bronze while being generally inferior. However soon iron forging techniques improved to make better quality metals and eventually surpassed Bronze ins strength and hardness, although bronze was superior in terms of other applications such a sea faring vessels as bronze is resistant to corrosion. Eventually during the Iron Age, Steel was discovered by adding carbon to the iron which is both lighter and stronger than normal iron and truly surpassed both iron and bronze.
Iron vs Steel
The terms iron and steel are often used interchangeably, but are in fact two quite different metals. Iron is generally brittle and heavy compared to steel, where as steel is iron with carbon added increasing the strength and reducing the weight. Steel was used during the Iron Age as it is an alloy of iron and carbon, but the two are in fact different metals.