siege failed to break Caesar's lines, and the
defenders were starved into submission. The crisis was over, although
another year was required before the revolting tribes were all reduced to
submission and the Roman authority re-established (51 B. C.). Caesar used
all possible mildness in his treatment of the conquered and the Gauls were
not only pacified but won over. In the days to come they were among his
most loyal supporters. The conquest of Gaul was an event of supreme
importance for the future history of the Roman empire, and for the
development of European civilization as well. For the time _Gallia comata_
was not formed into a province. Its peoples were made allies of Rome,
under the supervision of the governor of Narbonese Gaul, under obligation
to furnish troops and for the most part liable to a fixed tribute.
Caesar's campaign in Gaul had given him the opportunity to develop his
unusual military talents and to create a veteran army devoted to himself.
His power had become so great that both Pompey and the Optimates desired
his destruction and he was in a position to refuse to be eliminated
without a struggle. The plots laid in Rome to deprive him of his power had
made him hasten to quell the revolt of the Gauls with all speed. When this
was accomplished he was free to turn his attention to Roman affairs.

*Crassus in Syria, 55-53 B. C.* After the assignment of the provinces by
the Trebonian Law in 55 B. C., Crassus set out for Syria intending to win
military power and prestige by a war against the Parthians, an Asiatic
people who, once the subjects of the Persians and Seleucids, had
established a kingdom which included the provinces of the Seleucid empire
as far west as the Euphrates. Crassus had no real excuse for opening
hostilities, but the Parthians were a potentially dangerous neighbor and a
campaign against them gave promise of profit and glory. Accordingly, in 54
B. C., Crassus made a short incursion into Mesopotamia and then withdrew
to Syria. The next year he again crossed the Euphrates, intending to
penetrate deeply into the enemy's country. But he had underestimated the
strength of the Parthians and the difficulties of desert warfare. In the
Mesopotamian desert near Carrhae his troops were surrounded and cut to
pieces by the Parthian horsemen; Crassus himself was enticed into a
conference and treacherously slain, and only a small remnant of his force
escaped (53 B. C.). But the Parthians were slow in