Nearly all that is known about the life of Jesus, also called Jesus Christ, after whom Christianity is named, is contained in the four Gospels of the New Testament, particularly those of Mark, Matthew, and Luke. These accounts were written 60 to 100 or more years after the birth of Christ by men of different temperaments. They differ in some details but agree in all essentials. Jesus himself left no writings. Aside from mere mention by two Roman historians, in works written within a century after his death, the secular historians of his time said nothing about this man who has had such a profound influence on the life and thought of the world.
A new epoch in the history of the Roman Empire began with the accession
of Diocletian to the throne in A.D. 284. From that time the old names of
consul, tribune, etc., belonging to the republic lost their significance, and
even the senate was practically abolished. Thenceforth the empire became an
oriental sovereignty. In the year 292, having previously associated with
himself one colleague, Maximianus Herculius, Diocletian created two Caesars:
the one, Galerius Maximianus, to act as his subordinate in the East; the
other, Constantius Chlorus, to divide the government of the western provinces
with Maximianus Herculius.