The definition of an empire is: when a single entity has supreme rule and power over a vast area of territory, which consists of peoples of different ethnicity and nationality. This list is based on the influence, longevity and power of the various empires, and, as you will see, it contains at least one or two entries that may strike some as controversial. My one requirement for this list is that the empire must have been ruled – for at least a majority of the time – by an emperor or king. This excludes modern so-called empires such as the United States and Soviet Union. The entries here are listed roughly by influence and size.