But apparently Emperor Tiberius had him easily beat in terms of wealth with a net worth of a whopping 625 million denarii. Where did the Romans get the gold & silver to mint all their silver & gold coinage such as the denarius & aureus? The Athenians were able to mint all their Athenian silver owls due to the very productive Mines of Laurion. (This discovery meant that at the beginning of the second Persian invasion of Greece, the Athenian state had at its disposal 3,000 tons of silver. Rather than distribute this wealth amongst the citizens of Athens, Themistocles proposed that this money should be used to construct 200 triremes, which were used to conduct the naval campaign against Persia which culminated in victory at the Battle of Salamis in 480 BC.) But did the Romans have productive silver & gold mines as well? Or did they get most of their precious metals from conquest?