The five rulers—Nerva, Trajan, Hadrian, Antoninus Pius,
and Marcus Aurelius—whose reigns cover the greater part of the second century,
are sometimes called the Antonine Caesars, because two of them bore the name
Antoninus. They are better known as the "Good Emperors," a title
which well describes them. Under their just and beneficent government the empire
reached its greatest prosperity.
TRAJAN THE CONQUEROR
The emperor Trajan rivaled Julius Caesar in military
ability and enlarged the Roman world to the widest limits it was ever to
attain. His first conquests were in Europe and resulted in the annexation of
Dacia, an extensive territory north of the Danube. Thousands of colonists
settled in Dacia and spread everywhere the language and arts of Rome. Its
modern name (Rumania) bears witness to Rome's abiding influence there. Trajan's
campaigns in Asia had less importance, though in appearance they were more
splendid. He drove the Parthians from Armenia and conquered the Tigris-
Euphrates valley. To hold in subjection such distant regions only increased the
difficulty of guarding the frontiers. Trajan's successor, Hadrian, at once
abandoned them.
