The Roman Empire to the T-riumph of Christianity 305 of the most brutal force. Diocletian' increased the size of the The army army fourfold in spite of the additional expense and the in- barbarians creased burden of taxation. A vicious circle was thus set up. More troops cost more money, but they also meant greater ability to suppress disorders and collect taxes. The decreasing population of the Empire was insufficient to furnish the troops for the increased army. Diocletian w^as obliged to allow whole tribes of German barbarians to cross the border as military colonies furnishing troops for his great army. Thus the bar- barians were enlisted in the Roman legions to help keep out their fellow Germans. Julius Caesar was the first to give them a place among his soldiers. This custom became more and more common, until, finally, whole armies were German, entire tribes being enlisted under their own chiefs. Some of the Germans rose to be distinguished generals ; others attained important positions as officials of the government. In order to replenish the shrinking population likewise, great Population oi numbers of the German tribes were encouraged to settle within a^d the^^^^ the Empire, where they became coloni. Constantine (306- ^a^j.^^rians 337 A.D.) is said to have called in three hundred thousand of a single people. In this way it came about that a great many of the inhabitants of the Roman Empire were Germans before the great invasions, and the line dividing the citizens of the Roman Empire from the barbarians was already growing indistinct. As the Empire declined in strength and prosperity and was Decline of gr adually permeated by the barbarians, its art and literature and art rapidly degenerated. The buildings and monuments of Rome after Marcus Aurelius incline toward tawdry vulgarity in design and barbarous crudity in execution. The writings of the deca- dent Romans of this age fell far below the standard of the great literary men of the golden age of Augustus. Nor did the readers of the time demand anything better. The distinction of Cicero's clear style lost its charm for the readers of the fourth and fifth centuries, and a flowery kind of rhetoric took its place. No