Every nation, every society has its share of historical memories. They include, most obviously, the experiences of people who lived through past events, as they recall them. Then there is the record, written down in textbooks or literary works transmitted to generations who came after these events, but relived them vicariously, trusting in the accuracy of their national historians. Often historical records are magnified—or smudged out—by popular myths. In some cases, whether because of wars, revolutions, or other political upheavals, the records for a period of history are defective or totally missing from the national memory.