Metal connotes hardness and coldness in many aspects. Apart from these apparent physical characteristics, gold in particular has connotations of greed, money and power. Stories associated with gold usually include incredible greed or envy, and uncontrollable lust for money and power. Like many enterprises that begin with mostly noble intentions, the Roman Empire ultimately became a greed machine that destroyed many civilizations around it, simultaneously destroying itself. The golden coin-like disks sewn to the bottoms of the sandals help the shoes to be representative of all Roman soldiers: walking on gold wherever they tread, crushing all things underneath their soles of metal.
