=Marcus Aurelius.=—­Marcus Aurelius has been termed the Philosopher on the Throne.  He governed from a sense of duty, against his disposition, for he loved solitude; and yet he spent his life in administration and the command of armies.  His private journal (his “Thoughts”) exhibits the character of the Stoic—­virtuous, austere, separated from the world, and yet mild and good.  “The best form of vengeance on the wicked is not to imitate them; the gods themselves do good to evil men; it is your privilege to act like the gods.”

=Conquests of the Antonines.=—­The emperors of the first century had continued the course of conquest; they had subjected the Britons of England, the Germans on the left bank of the Rhine, and in the provinces had reduced several countries which till then had retained their kings—­Mauretania, Thrace, Cappadocia.  The Rhine, the Danube, and the Euphrates were the limits of the empire.

The emperors of the second century were almost all generals; they had the opportunity of waging numerous wars to repel the hostile peoples who sought to invade the empire.  The enemies were in two quarters especially: 

  1.  On the Danube were the Dacians, barbarous people, who occupied
  the country of mountains and forests now called Transylvania.

  2.  On the Euphrates was the great military monarchy of the
  Parthians which had its capital at Ctesiphon, near the ruins of
  Babylon, and which extended over all Persia.

Trajan made several expeditions against the Dacians, crossed the Danube, won three great battles, and took the capital of the Dacians (101-102).  He offered them peace, but when they reopened the war he resolved to end matters with them:  he had a stone bridge built over the Danube, invaded Dacia and reduced it to a Roman province (106).  Colonies were transferred thither, cities were built, and Dacia became a Roman province where Latin was spoken and Roman customs were assimilated.  When the Roman armies withdrew at the end of the third century, the Latin language remained and continued throughout the Middle Ages, notwithstanding the invasions of the barbarian Slavs.  It is from Transylvania (ancient Dacia) that the peoples came from the twelfth to the fourteenth century who now inhabit the plains to the north of the Danube.  It has preserved the name of Rome (Roumania) and speaks a language derived from the Latin, like the French or Spanish.  Trajan made war on the Parthians also.  He crossed the Euphrates, took Ctesiphon, the capital, and advanced into Persia, even to Susa, whence he took away the massive gold throne of the kings of Persia.  He constructed a fleet on the Tigris, descended the stream to its mouth and sailed into the Persian Gulf; he would have delighted, like Alexander, in the conquest of India.  He took from the Parthians the country between the Euphrates and the Tigris—­Assyria and Mesopotamia—­and erected there two Roman provinces.