Dan Lipert is VP of Engineering at Gitcoin, Advisor at Couger. Formerly, CTO at Hoard, Lead Engineer at Trapit, Founder of Hyperlayer and Techno Garden. Historically, it has been good, strong currencies that have driven out bad, weak currencies. Over the span of several millennia, strong currencies have dominated and driven out weak in international competition. The Persian daric, the Greek tetradrachma, the Macedonian stater, and the Roman denarius did not become dominant currencies of the ancient world because they were "bad" or "weak." The florins, ducats and sequins of the Italian city-states did not become the "dollars of the Middle Ages" because they were bad coins; they were among the best coins ever made. The pound sterling in the 19th century and the dollar in the 20th century did not become the dominant currencies of their time because they were weak. Consistency, stability and high quality have been the attributes of great currencies that have won the competition for use as international money. - Robert Mundell, "Uses and Abuses of Gresham's Law in the History of Money"