http://en.wikipedia.org/wiki/Chicory
“The cultivated chicory plant has a history reaching back to ancient Egyptian time. Medieval monks raised the plants and when coffee was introduced to Europe, the Dutch thought that chicory made a lively addition to the bean drink.
In the United States chicory root has long been used as a substitute for coffee in prisons.[54] By the 1840s, the port of New Orleans was the second largest importer of coffee (after New York).[53] Louisianans began to add chicory root to their coffee when Union naval blockades during the American Civil War cut off the port of New Orleans, thereby creating a long-standing tradition.[53]”
This would make sense considering that the world went into a Dark Ages after the collapse of the Ancient Egyptian Empire much as it did after the collapse of the Roman Empire.