James Bryce, Encyclopædia Britannica, Ninth Edition…
“ EMPIRE, a term used to denote either the territories governed by a person bearing the title of emperor (see Emperor) , or, more generally, any extensive dominion. The historians of a former age were accustomed to enumerate a succession of great empires, and especially the Babylonian and Assyrian, Medo-Persian, and the Macedonian, which had embraced the greater part of the civilized world before the rise of Roman power, but that system has now been abandoned. ”
