Today, the American dollar is legal tender in as many as seven sovereign nations besides the United States of America. But there was a time, not too long ago, when another currency enjoyed a similar influence far from home. It was legal tender in half a dozen countries besides its own, all of them in a region that influences the global economy more than any other on the planet today. It's the Indian rupee. This is the rarely-told story of how a currency from a nation as impoverished as ours went on to enjoy such clout in one of the wealthiest parts of the world, and how it ended.