The Persians created a set of standardized metal coins during this time period. Why was this important to the development of trade?​

The Persian daric was a gold coin which, along with a similar silver coin, the siglos, represented the bimetallic monetary standard of the Achaemenid Persian Empire. ... Darius considered such encroachment a crime punishable by death since the right of coinage was treated as an exclusively royal prerogative.

Explanation:

during the debate over his landmark energy policy proposal, president jimmy carter failed to consult one of the most powerful senators, louisiana’s russell long, who would have a big say over whether the legislation moved through the upper chamber. this was classic carter. with a strong distaste for congressional politics, the president simply refused to do what most other presidents would consider routine, such as courting key senators. long became so irate with the president that when he was finally invited to a white house dinner, he stood up to ask a question and, before doing so, proceeded to sarcastically introduce himself: “i’m russell long, chairman of the senate finance committee.”

this interaction is a revealing moment in stuart e. eizenstat’s fascinating new history of carter’s presidency. the former peanut farmer from georgia was a president who, according to conventional wisdom, didn’t care much for party politics; nonetheless, in eizenstat’s view, carter’s legacy on domestic and foreign policy has been vastly underappreciated. the author paints carter as a “bold and determined” leader who bravely attacked the challenges of his time. eizenstat goes so far as to argue that carter might very well be the most successful one-term president in american history.