act of war. Constantine won a
signal victory at Adrianople and his son Crispus destroyed the fleet of
Licinius at the Hellespont. These disasters induced Licinius to withdraw
to Asia Minor. There he was completely defeated by Constantine near
Chrysopolis (18 September, 324 A. D.). Licinius surrendered upon assurance
of his life, but the following year he was executed on a charge of
treason. Constantine was now sole emperor.

*Constantine sole emperor, 324-337 A. D.* Constantine's administrative
policy followed in the steps of Diocletian, whose organization he
elaborated and perfected in many respects. The praetorian prefecture was
deprived of its military authority, which was conferred upon the
newly-created military offices of master of the horse and the foot
(_magister equitum_ and _peditum_). This completed the separation between
the military and civil offices. Diocletian's field force was strengthened
by the creation of new mobile units, and his efficient army enabled
Constantine to defend the empire against all barbarian attacks. Upon waste
lands within the frontiers he settled Sarmatians and Vandals, while he
greatly increased the barbarian element in the army as a whole, but
particularly among the officers of higher rank.

*Constantinople, 330 A. D.* Of special importance for the future history
of the empire was the founding of a new capital, called Constantinople, on
the site of ancient Byzantium. After four years' preparation, the new city
was formally dedicated on 11 May, 330 A. D. The choice of the site of the
new capital of the empire was determined by its strategic importance. It
was conveniently situated with respect to the eastern and Danubian
frontiers, and well adapted as a link between the European and Asiatic
parts of the empire. The aim of the emperor was to make Constantinople a
new Rome, and he gave it the organization and the institutions of Rome on
the Tiber. A new Senate was established there; likewise the public
festivals and free bread for the populace. For the latter purpose the
grain of Egypt was diverted from Rome to Constantinople.

*Constantine and the succession.* Like Diocletian, Constantine realized
the necessity of having more than a single ruler for the empire, but he
determined to choose his associates from the members of his own household.
Accordingly, following Crispus and Constantine, his younger sons,
Constantius and Constans, were given the title of Caesar, while
Licinianus,