Modern plate tectonic theory, the development of earthquake prediction and the mitigation of earthquake hazards are based on the study of earthquakes during the twentieth century. Investigation of earthquakes over a much longer period, although in no way invalidating the global importance of plate tectonics, shows that patterns of seismic activity do change with time and that areas of intense seismic activity in the historical past are often gaps of earthquake activity today. This study of the historical seismicity of Iran over the last thirteen centuries not only shows this quite clearly but also reveals a long-term tectonic pattern which is different from that deduced from short-term observations. The historical data provides the basis for the development of earthquake prediction models and for long-term earthquake hazard assessment. This book will be of equal interest to earth scientists, seismologists, historical geographers and orientalists.