(imperium), in political geography, a large extent of land, under the jurisdiction or government of an emperor. In ancient history we read of four great monarchies or empires, namely, that of the Babylonians, Chaldeans, and Assyrians; that of the Medes and Persians; that of the Greeks; and that of the Romans. The first subsisted from the time of Nimrod, who founded it in the year of the world 1800, according to the computation of Usher, till that of Sardanapalus their last king in 3257, and consequently lasted above 1450 years. The empire of the Medes commenced under Arbaces, in the year of the world 3257, was united to that of the Babylonians Empire and Persians under Cyrus, in 3468, and closed with the death of Darius Codomannus in 3674. The Grecian empire lasted only during the reign of Alexander the Great, beginning in the year of the world 3674, and terminating with the death of this conqueror in 3681, his conquests having been divided amongst his captains. The Roman empire commenced with Julius Caesar, when he was made perpetual dictator, in the year of the city 708, and of the world 3956, forty-eight years before Christ. The seat of the empire was removed to Byzantium by Constantine, in the year of our Lord 334; and the East and West were then united under the title of the Roman empire, till the Romans proclaimed Charlemagne emperor, in the year 800. From this epoch the East and West formed two separate empires. That of the East, governed by Greek emperors, commenced in the year 302; and being gradually weakened, terminated under Constantine Palaeologus in 1453. The western empire was afterwards known by the appellation of the empire, or German empire. Antiquaries distinguish between the medals of the Upper and Lower Empire. The curious only value those of the Upper Empire, which commenced with Caesar or Augustus, and ended in the year of Christ 260. The Lower Empire comprehended near 1200 years, reckoning downwards till the destruction of Constantinople in 1453. Two ages, or periods, of the Lower Empire are usually distinguished; the first beginning where the Upper ends, namely, with Aurelian, and terminating with Anastasius, including 200 years; and the second beginning with Anastasius, and ending with the Paleologi, which includes 1000 years.

or The Empire, used absolutely and without any addition, signifies the empire of Germany, which is also called in juridical acts and laws the holy Roman empire. It had its beginning at the commencement of the ninth century, when Charlemagne was created first emperor by Pope Leo III, who put the crown on his head in St Peter's church on Christmas day in the year 800.